#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#define DEBUG
#define PI 3.14159
#define string_size 100

char input_string[string_size];
void RemoveSpaces(char *source);
double solve(char *equation_s);

int main (void)
{
int option, choice, selection;
double first_Num, sec_Num, third_Num, area, rad1, rad2, rad3, base, height, volume;
double result;
    do
    {
        printf("Michael's Calculator\n");
        printf("\nChoose what calculation to perform\n");
        printf("\t1 - Standard Arithmetic Calculator\n");
        printf("\t2 - Area of Shapes\n");
        printf("\t3 - Volume of Shapes\n");
        printf("(Enter a zero to exit) \n");
        printf("\nMake a selection: ");
        scanf("%d", &choice);

    switch (choice)
    {
    case 1:
    {
        do
            {
            system("cls");
            printf("Standard Arithmetic Calculator\n");
            printf("Enter an equation to solve\n");
            fflush(stdin);
            gets_s(input_string, string_size);
            RemoveSpaces(input_string);
            solve(input_string);
            result = atof(input_string);
            printf("\nAnswer: %.4f\n",result);
            printf("\nDo you want to do another operation?\n1) Yes 2) No\n");
            scanf("%d",&option);
        }
        while (option ==1);
        system("cls");
        break;
    }
    case 2:
            {
                do
                {
                    printf("\nFIND THE AREA OF A SHAPE\n\n");
                    printf("Which shape?\n");
                    printf("\t1 - Square\n");
                    printf("\t2 - Rectangle\n");
                    printf("\t3 - Parallelogram\n");
                    printf("\t4 - Trapezoid\n");
                    printf("\t5 - Circle\n");
                    printf("\t6 - Ellipse\n");
                    printf("\t7 - Triangle\n");
                    printf("\t8 - Go back to previous menu\n");
                    printf("\nMake a selection: ");
                    scanf("%d", &selection);

                        switch (selection)
                        {
                            case 1:
                            {
                                printf("\nArea Of A Square\n");
                                printf("\nEnter length of a side of the square: ");
                                scanf("%lf", &first_Num);
                                while (first_Num <= 0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter length of a side of the square: ");
                                    scanf("%lf", &first_Num);
                                }
                                area = first_Num * first_Num;
                                printf("\nThe area of a square with a side of %.4f is \n%.4f\n\n", first_Num, area);
                                break;
                            }
                            case 2:
                            {
                                printf("\nArea Of A Rectangle\n");
                                printf("\nEnter width: ");
                                scanf("%lf", &first_Num);
                                while (first_Num <=0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter width: ");
                                    scanf("%lf", &first_Num);
                                }
                                printf("Enter height: ");
                                scanf("%lf", &sec_Num);
                                while(sec_Num <= 0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter height: ");
                                    scanf("%lf", &sec_Num);
                                }
                                area = first_Num * sec_Num;
                                printf("\nThe area of a rectagle with sides of %.4f and %.4f is \n%.4f\n\n", first_Num, sec_Num, area);
                                break;
                            }
                            case 3:
                            {
                                printf("\nArea Of A Parallelogram\n\n");
                                printf("Enter base: ");
                                scanf("%lf", &first_Num);
                                while (first_Num <=0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter base: ");
                                    scanf("%lf", &first_Num);
                                }
                                printf("Enter height: ");
                                scanf("%lf", &sec_Num);
                                while(sec_Num <= 0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter height: ");
                                    scanf("%lf", &sec_Num);
                                }
                                area = first_Num * sec_Num;
                                printf("\nThe area of a parallelogram with sides of %.4f and %.4f is \n%.4f\n\n", first_Num, sec_Num, area);
                                break;
                            }
                            case 4:
                            {
                                printf("\nArea Of A Trapezoid\n\n");
                                printf("Enter base-1: ");
                                scanf("%lf", &first_Num);
                                while (first_Num <=0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter base-1: ");
                                    scanf("%lf", &first_Num);
                                }
                                printf("Enter base-2: ");
                                scanf("%lf", &sec_Num);
                                while(sec_Num <= 0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter base-2: ");
                                    scanf("%lf", &sec_Num);
                                }
                                printf("Enter height: ");
                                scanf("%lf", &third_Num);
                                while(third_Num <= 0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter height: ");
                                    scanf("%lf", &third_Num);
                                }
                                area = (third_Num/2) * (first_Num + sec_Num);
                                printf("\nThe area of a trapezoid with a base-1 of %.4f, a base-2 of %.4f, and a height of %.4f is \n%.4f\n\n", first_Num, sec_Num, third_Num, area);
                                break;
                            }
                            case 5:
                            {
                                printf("\nArea Of A Circle\n\n");
                                printf("Enter the radius: ");
                                scanf("%lf", &rad1);
                                while(rad1 <= 0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter the radius: ");
                                    scanf("%lf", &rad1);
                                }
                                area = (rad1 * rad1) * PI;
                                printf("The area of a circle with a radius of %.4f is \n%.4f\n\n", rad1, area);
                                break;
                            }
                            case 6:
                            {
                                printf("\nArea Of An Ellipse\n\n");
                                printf("Enter radius-1: ");
                                scanf("%lf", &rad1);
                                while(rad1 <= 0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter radius-1: ");
                                    scanf("%lf", &rad1);
                                }
                                printf("Enter radius-2: ");
                                scanf("%lf", &rad2);
                                while(rad2 <= 0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter radius-2: ");
                                    scanf("%lf", &rad2);
                                }
                                area = (rad1 * rad2) * PI;
                                printf("The area of an ellipse with a radius-1 of %.4f and a radius-2 of %.4f is \n%.4f", rad1, rad2, area);
                                break;
                            }
                            case 7:
                            {
                                printf("\nArea Of A Triangle\n\n");
                                printf("Enter base: ");
                                scanf("%lf", &base);
                                while(base<=0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter base: ");
                                    scanf("%lf", &base);
                                }
                                printf("Enter height: ");
                                scanf("%lf", &height);
                                while(height<=0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter height: ");
                                    scanf("%lf", &height);
                                }
                                area = (base * height) / 2;
                                printf("The area of a triangle with a base of %.4f and a height of %.4f is \n%.4f", base, height, area);
                                break;
                            }
                            default:
                            {
                                if (selection !=8)
                                {
                                    printf("\nYour selection was not from the menu\n");
                                    printf("Please try again.\n\n");
                                }

                            }break;
                        }
                }
                while (selection != 8);
                break;
            }
    case 3:
            {
                do
                {
                    printf("\nFIND THE VOLUME OF A SHAPE\n\n");
                    printf("Which shape?\n");
                    printf("\t1 - Cube\n");
                    printf("\t2 - Rectangular Prism\n");
                    printf("\t3 - Cone\n");
                    printf("\t4 - Cylinder\n");
                    printf("\t5 - Pyramid\n");
                    printf("\t6 - Sphere\n");
                    printf("\t7 - Ellipsoid\n");
                    printf("\t8 - Go back to previous menu\n");

                    printf("\nMake a selection: ");
                    scanf("%d", &selection);

                        switch (selection)
                        {
                            case 1:
                            {
                                printf("\nVolume Of A Cube\n\n");
                                printf("Enter length of a side of the cube: ");
                                scanf("%lf", &first_Num);
                                while (first_Num <= 0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter length of a side of the square: ");
                                    scanf("%lf", &first_Num);
                                }
                                volume = first_Num * first_Num * first_Num;
                                printf("\nThe volume of a cube with a side of %.4f is \n%.4f\n\n", first_Num, volume);
                                break;
                            }
                            case 2:
                            {
                                printf("\nVolume Of A Rectangular Prism\n\n");
                                printf("Enter width: ");
                                scanf("%lf", &first_Num);
                                while (first_Num <=0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter width: ");
                                    scanf("%lf", &first_Num);
                                }
                                printf("Enter height: ");
                                scanf("%lf", &sec_Num);
                                while(sec_Num <= 0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter height: ");
                                    scanf("%lf", &sec_Num);
                                }
                                printf("Enter depth: ");
                                scanf("%lf", &third_Num);
                                while (first_Num <=0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter depth: ");
                                    scanf("%lf", &third_Num);
                                }
                                volume = first_Num * sec_Num * third_Num;
                                printf("\nThe volume of a rectagular prism with a width of %.4f, a height of %.4f and a depth of %.4f is \n%.4f\n\n",
                                first_Num, sec_Num, third_Num, volume);
                                break;
                            }
                            case 3:
                            {
                                printf("\nVolume Of A Cone\n\n");
                                printf("Enter radius: ");
                                scanf("%lf", &first_Num);
                                while (first_Num <=0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter radius: ");
                                    scanf("%lf", &first_Num);
                                }
                                printf("Enter height: ");
                                scanf("%lf", &sec_Num);
                                while(sec_Num <= 0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter height: ");
                                    scanf("%lf", &sec_Num);
                                }
                                volume = (PI * (first_Num * first_Num) * sec_Num)/3;
                                printf("\nThe volume of a cone with a radius of %.4f and a height %.4f is \n%.4f\n\n", first_Num, sec_Num, volume);
                                break;
                            }
                            case 4:
                            {
                                printf("\nVolume Of A Cylinder\n\n");
                                printf("Enter radius: ");
                                scanf("%lf", &first_Num);
                                while (first_Num <=0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter radius: ");
                                    scanf("%lf", &first_Num);
                                }
                                printf("Enter height: ");
                                scanf("%lf", &sec_Num);
                                while(sec_Num <= 0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter height: ");
                                    scanf("%lf", &sec_Num);
                                }
                                volume = ((first_Num * first_Num) * sec_Num * PI);
                                printf("\nThe volume of a cylinder with a radius of %.4f and a height of %.4f is \n%.4f\n\n", first_Num, sec_Num, volume);
                                break;
                            }
                            case 5:
                            {
                                printf("\nVolume Of A Pyramid\n\n");
                                printf("Enter the area of the base: ");
                                scanf("%lf", &first_Num);
                                while(first_Num <= 0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter the area of the base: ");
                                    scanf("%lf", &first_Num);
                                }
                                printf("Enter the height: ");
                                scanf("%lf", &sec_Num);
                                volume = (first_Num * sec_Num) /3;
                                printf("\nThe volume of a pyramid with a base area of %.4f and a height of %.4f is \n%.4f\n\n", first_Num, sec_Num, volume);
                                break;
                            }
                            case 6:
                            {
                                printf("\nVolume Of A Sphere\n\n");
                                printf("Enter radius: ");
                                scanf("%lf", &rad1);
                                while(rad1 <= 0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter radius: ");
                                    scanf("%lf", &rad1);
                                }
                                volume =  ((rad1 * rad1 * rad1) * PI) / 0.75;
                                printf("\nThe volume of a sphere with a radius of %.4f is \n%.4f", rad1, volume);
                                break;
                            }
                            case 7:
                            {
                                printf("\nVolume Of An Ellipsoid\n\n");
                                printf("Enter radius-1: ");
                                scanf("%lf", &rad1);
                                while(rad1<=0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter radius-1: ");
                                    scanf("%lf", &rad1);
                                }
                                printf("Enter radius-2: ");
                                scanf("%lf", &rad2);
                                while(rad2<=0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter radius-2: ");
                                    scanf("%lf", &rad2);
                                }
                                printf("Enter radius-3: ");
                                scanf("%lf", &rad3);
                                while(rad3<=0)
                                {
                                    printf("\nERROR!! Distance must be a positive number\n\n");
                                    printf("Enter radius-3: ");
                                    scanf("%lf", &rad3);
                                }
                                volume = ((rad1 * rad2 * rad3) * PI) / 0.75;
                                printf("\nThe volume of an ellipsoid with a radius-1 of %.4f, a radius-2 of %.4f and a radius-3 of %.4f is \n%.4f",
                                rad1, rad2, rad3, volume);
                                break;
                            }
                            default:
                            {
                                if (selection !=8)
                                {
                                    printf("\nYour selection was not from the menu\n");
                                    printf("Please try again.\n\n");
                                }

                            }break;
                        }


                    }while (selection != 8);
                break;
            }

            default:
            {
                if (choice != 0)
                {
                    printf("\nYour selection was not from the menu\n");
                    printf("Please try again.\n\n");
                }
                break;
            }
        }
        while (option !=2);
    }
    while (choice !=0);
return (0);
}

void RemoveSpaces(char *source)//disregards any spaces
{
    char temp_string[string_size];
    int i,j,size;
    size = strnlen_s(source,string_size);
    temp_string[0] = source[0];
    j = 1;
    for (i=1;i<=size;i++)
    {
        // if subtraction and preseading charitor is an operation, then change to adding a negitive number.
        if ((source[i] == '-') &&! ((temp_string[j-1] == '*') || (temp_string[j-1] == '/') || (temp_string[j-1] == '+') || (temp_string[j-1] == '^')))
        {
            temp_string[j] = '+';
            j++;
        }
        // remove all spaces
        if (source[i] == ' ')
        {
        }
        else
        {
            temp_string[j] = source[i];
            j++;
        }
    };
    strcpy_s(source,string_size,temp_string);
}

int exist_paren(char *equation_s) //check for parentheses
{
    int length,i, rc=0;
    length=strnlen_s(equation_s,string_size);
    for(i=0; i<length; i++) // checks for parentheses and returns a 1. if no parentheses found, returns a 0
    {
        if((equation_s[i] == '(' )||(equation_s[i]== ')' ))
        {
        rc=1;
        break;
        }
    }
    return (rc);
}

int exist_expon(char *equation_s) //check for exponents
{
    int length,i, rc=0;
    length=strnlen_s(equation_s,string_size);
    for(i=0; i<length; i++) // checks for carrot
    {
        if(equation_s[i] == '^' )
        {
        rc=1;
        break;
        }
    }
    return (rc); //if found, returns a 1. if not found returns a 0
}


int exist_mult(char *equation_s) //check for multiplication and division
{
    int length,i, rc=0;
    length=strnlen_s(equation_s,string_size);
    for(i=0; i<length; i++) // checks for carrot
    {
        if((equation_s[i] == '*' )||(equation_s[i] == '/' ))
        {
        rc=1;
        break;
        }
    }
    return (rc); //if found, returns a 1. if not found returns a 0
}


int exist_add(char *equation_s) //check for addition and subraction
{
    int length,i, rc=0;
    length=strnlen_s(equation_s,string_size);
    for(i=0; i<length; i++)
    {
        if(equation_s[i] == '+' )
        {
        rc=1;
        break;
        }
    }
    return (rc); //if found, returns a 1. if not found returns a 0
}

double solve_paren(char *equation_s)
{
int open_paren=0, close_paren=0, i;
double result;
char paren_string[string_size], temp_string1[string_size],temp_string2[string_size];
    for (i=0; i<strnlen_s(equation_s,string_size); i++) //continues until i = the length of the string entered
    {
        if(equation_s[i] == '(' )
        {
            open_paren = i;  //searches for open parentheses, and stores position in open_paren
        }
        if(equation_s[i] == ')' )
        {
            close_paren = i; //searches for close parentheses, and stores position in closes_paren
            break;
        }
    }
    strncpy_s(paren_string, string_size, &equation_s[open_paren+1], close_paren- open_paren-1);
    result=solve(paren_string);
    //changes a double negative to a positive
    if(result<0)  //checks to see if number inside parentheses is negative
    {
        if(equation_s[open_paren-1] =='-') //checks if result is to be negated
        {
            result = result *-1;   // changes to a positive
            open_paren -=1;   // erases negative sign
        }
    }
    sprintf(temp_string1,"%lf", result); // converts results (double) into an array and stores it in temp_string1
    strcpy(temp_string2,&equation_s[close_paren+1]); //copies remainder of string after closing parenthese
    strcpy(&equation_s[open_paren],temp_string1);
    i = strnlen_s(equation_s, string_size); // i is length of string size in equation_s
    strcpy(&equation_s[i],temp_string2);
    return result;
}

double solve_expon(char *equation_s)
{
int last_op= strnlen_s(equation_s,string_size), first_op=0, carrot=0, i;
double result, r1, r2;
char base[string_size],exponent[string_size], temp_string1[string_size], temp_string2[string_size];
    // Find left operand for exponent
    // Will be between first_op and carrot
    for (i=0; i<strnlen_s(equation_s,string_size); i++)
    {
        if((equation_s[i]=='+')||(equation_s[i]=='*')||(equation_s[i]=='/'))
        {
            first_op = i+1;
        }
        if (equation_s[i]=='^')
        {
            carrot = i;
            break;
        }

    }
    // Find right operand for exponent
    // will be between carrot and last_op
    for (i=carrot+1; i < strnlen_s(equation_s,string_size); i++)
    {
        if((equation_s[i]=='+')||(equation_s[i]=='*')||(equation_s[i]=='/'))
        {
            last_op=i-1;
            break;
        }
    }
    strncpy_s(base, string_size, equation_s+first_op, carrot - first_op);
    r1= atof(base);
    strncpy_s(exponent, string_size, equation_s+carrot+1, last_op - carrot);
    r2= atof(exponent);
    result = pow(r1,r2);
    sprintf(temp_string1,"%f", result); // converts results (double) into an array and stores it in temp_string1
    strcpy_s(&temp_string2,string_size,&equation_s[last_op+1]); //copies string in equation_s and stores it in temp_string2
    strcpy_s(&equation_s[first_op],string_size, &temp_string1);
    i = strnlen_s(equation_s, string_size); // i is length of string size in equation_s
    strcpy_s(&equation_s[i], string_size, temp_string2);
    return result;
}

double solve_mult(char *equation_s)
{
int last_op= strnlen_s(equation_s,string_size), first_op=0, operation=0, i;
double result, r1, r2;
char operand1[string_size],operand2[string_size], temp_string1[string_size], temp_string2[string_size];

    for (i=0; i<strnlen_s(equation_s,string_size); i++)
    {
        if(equation_s[i]=='+') //looks for + sign and stores position
        {
            first_op = i+1;
        }
        if ((equation_s[i]=='*')||(equation_s[i]=='/'))
        {
            operation = i;
            break;
        }

    }
    for (i=operation+1; i < strnlen_s(equation_s,string_size); i++)
    {
        if((equation_s[i]=='+')||(equation_s[i]=='*')||(equation_s[i]=='/'))
        {
            last_op=i-1;
            break;
        }
    }
    strncpy_s(operand1, string_size, equation_s+first_op, operation - first_op);
    r1= atof(operand1);
    strncpy_s(operand2, string_size, equation_s+operation+1, last_op - operation);
    r2= atof(operand2);
    if(equation_s[operation]=='*')
    {
        result = r1*r2;
    }
    else
    {
        result = r1/r2;
    }
    sprintf(temp_string1,"%f", result); // converts results (double) into an array and stores it in temp_string1
    strcpy_s(&temp_string2,string_size,&equation_s[last_op+1]); //copies string in equation_s and stores it in temp_string2
    strcpy_s(&equation_s[first_op],string_size, &temp_string1);
    i = strnlen_s(equation_s, string_size); // i is length of string size in equation_s
    strcpy_s(&equation_s[i], string_size, temp_string2);
    return result;
}

double solve_add(char *equation_s)
{
int last_op= strnlen_s(equation_s,string_size), first_op=0, operation=0, i;
double result, r1, r2;
char operand1[string_size],operand2[string_size], temp_string1[string_size], temp_string2[string_size];

    for (i=0; i<strnlen_s(equation_s,string_size); i++)
    {
        if(equation_s[i]=='+')
        {
            operation = i;
            break;
        }
    }
    for (i=operation+1; i < strnlen_s(equation_s,string_size); i++)
    {
        if(equation_s[i]=='+') //finding next + sign
        {
            last_op=i-1;
            break;
        }
    }
    strncpy_s(operand1, string_size, equation_s+first_op, operation - first_op);
    r1= atof(operand1);
    strncpy_s(operand2, string_size, equation_s+operation+1, last_op - operation);
    r2= atof(operand2);
    if(equation_s[operation]=='+')
    {
        result = r1+r2;
    }
    else
    {
        result = r1-r2;
    }
    sprintf(temp_string1,"%f", result); // converts results (double) into an array and stores it in temp_string1
    strcpy_s(&temp_string2,string_size,&equation_s[last_op+1]); //copies string in equation_s and stores it in temp_string2
    strcpy_s(&equation_s[first_op],string_size, &temp_string1);
    i = strnlen_s(equation_s, string_size); // i is length of string size in equation_s
    strcpy_s(&equation_s[i], string_size, temp_string2);
    return result;
}

double solve(char *equation_s)
{
double result=0;
    while(exist_paren(equation_s)) //check for parentheses
    {
        result= solve_paren(equation_s); //if parentheses are in equation, goes to solve_paren function
    }
    while(exist_expon(equation_s)) // checks for carrot
    {
        result=solve_expon(equation_s); // if carrot is in equation, goes to slove_expon
    }
    while(exist_mult(equation_s))
    {
        result = solve_mult(equation_s);
    }
    while(exist_add(equation_s))
    {
        result = solve_add(equation_s);
    }
    return result;
}