/*********************************************
 *  THE SCIENTIFIC PIECE OF CRAP CALCULATOR  *
 *********************************************/
// BUGFIXED VERSION

#include <stdio.h>
#include <math.h>

double
rounddouble(double input, int precision)
{
    return floor(input * pow(10, precision) + 0.5) / pow(10, precision);
}

double
inputdouble(char *query)
{
    double          temp;
    while (1)
    {
        printf("%s", query);
        if (scanf(" %lf", &temp) == 1)
        {
            getchar();
            return temp;
        } else
        {
            while (getchar() != '\n')
            {
            }
        }
    }
}

char
inputrestricted(char *query, char *formatstring)
{
    int             temp;
    //BUGFIX
        while (1)
    {
        printf("%s", query);
        if (scanf(formatstring, (char *) &temp) == 1)
            //BUGFIX
        {
            getchar();
            return temp;
        } else
        {
            while (getchar() != '\n')
            {
            }
        }
    }

}

int
main(void)
{
    double          op_1, op_2, result, resultrounded;
    unsigned int    op1query = 0;
    unsigned int    exitflag = 0;
    unsigned int    precision = 3;
    unsigned char   operator;
    printf("**********************************************\n");
    printf("*  THE SCIENTIFIC PIECE OF CRAP CALCULATOR   *\n");
    printf("**********************************************\n\n");
    printf("VALID OPERATORS: + - * / ^ S C T L R . Q\n");
    printf("QUIT: Q\n");
    printf("DISCARD ANS RESULT: .\n");
    printf("ROUND RESULT: R\n");
    precision = inputrestricted("DISPLAY SIGN.DIGITS [A,0,1,3]: ", " %[aA013]") - 0X30;
    printf("%d", precision);
    op_1 = inputdouble("#: ");
    while (!exitflag)
    {
        switch (inputrestricted("OP: ", " %[+-*/^lLcCsStTqQrR.]"))
        {
        case '+':
            op_2 = inputdouble("+: ");
            result = op_1 + op_2;
            switch (precision)
            {
            case 0:
                printf("%.f + %.f = %.f\n", op_1, op_2, result);
                break;
            case 1:
                printf("%.1f + %.1f = %.1f\n", op_1, op_2, result);
                break;
            case 3:
                printf("%.3f + %.3f = %.3f\n", op_1, op_2, result);
                break;
            default:
                printf("%G + %G = %G\n", op_1, op_2, result);
                break;
            }
            break;
        case '-':
            op_2 = inputdouble("-: ");
            result = op_1 - op_2;
            switch (precision)
            {
            case 0:
                printf("%.f - %.f = %.f\n", op_1, op_2, result);
                break;
            case 1:
                printf("%.1f - %.1f = %.1f\n", op_1, op_2, result);
                break;
            case 3:
                printf("%.3f - %.3f = %.3f\n", op_1, op_2, result);
                break;
            default:
                printf("%G - %G = %G\n", op_1, op_2, result);
                break;
            }
            break;
        case '*':
            op_2 = inputdouble("*: ");
            result = op_1 * op_2;
            switch (precision)
            {
            case 0:
                printf("%.f * %.f = %.f\n", op_1, op_2, result);
                break;
            case 1:
                printf("%.1f * %.1f = %.1f\n", op_1, op_2, result);
                break;
            case 3:
                printf("%.3f * %.3f = %.3f\n", op_1, op_2, result);
                break;
            default:
                printf("%G * %G = %G\n", op_1, op_2, result);
                break;
            }
            break;
        case '/':
            if (op_2 = inputdouble("/: "))
            {
                result = (double) op_1 / (double) op_2;
                switch (precision)
                {
                case 0:
                    printf("%.f / %.f = %.f\n", op_1, op_2, result);
                    break;
                case 1:
                    printf("%.1f / %.1f = %.1f\n", op_1, op_2, result);
                    break;
                case 3:
                    printf("%.3f / %.3f = %.3f\n", op_1, op_2, result);
                    break;
                default:
                    printf("%G / %G = %G\n", op_1, op_2, result);
                    break;
                }
                break;
            } else
            {
                printf("? DIVISOR ZERO\n");
                break;
            }
            break;
        case '^':
            op_2 = inputdouble("^: ");
            if ((op_2 < 1 && op_1 > 0) || op_2 >= 1 || op_2 == 0)
            {
                result = pow(op_1, op_2);
                switch (precision)
                {
                case 0:
                    printf("%.f ^ %.f = %.f\n", op_1, op_2, result);
                    break;
                case 1:
                    printf("%.1f ^ %.1f = %.1f\n", op_1, op_2, result);
                    break;
                case 3:
                    printf("%.3f ^ %.3f = %.3f\n", op_1, op_2, result);
                    break;
                default:
                    printf("%G ^ %G = %G\n", op_1, op_2, result);
                    break;
                }
                break;
            } else
            {
                printf("? COMPLEX ROOT\n");
                break;
            }
            break;
        case 's':
        case 'S':
            result = sin(op_1 * M_PI / 180);
            switch (precision)
            {
            case 0:
                printf("SIN(%.f) = %.f\n", op_1, result);
                break;
            case 1:
                printf("SIN(%.1f) = %.1f\n", op_1, result);
                break;
            case 3:
                printf("SIN(%.3f) = %.3f\n", op_1, result);
                break;
            default:
                printf("SIN(%G) = %G\n", op_1, result);
                break;
            }
            break;
        case 'c':
        case 'C':
            result = cos(op_1 * M_PI / 180);
            switch (precision)
            {
            case 0:
                printf("COS(%.f) = %.f\n", op_1, result);
                break;
            case 1:
                printf("COS(%.1f) = %.1f\n", op_1, result);
                break;
            case 3:
                printf("COS(%.3f) = %.3f\n", op_1, result);
                break;
            default:
                printf("COS(%G) = %G\n", op_1, result);
                break;
            }
            break;
        case 't':
        case 'T':
            if (fmod(op_1 - 90, 180))
            {
                result = tan(op_1 * M_PI / 180);
                switch (precision)
                {
                case 0:
                    printf("TAN(%.f) = %.f\n", op_1, result);
                    break;
                case 1:
                    printf("TAN(%.1f) = %.1f\n", op_1, result);
                    break;
                case 3:
                    printf("TAN(%.3f) = %.3f\n", op_1, result);
                    break;
                default:
                    printf("TAN(%G) = %G\n", op_1, result);
                    break;
                }
            } else
            {
                printf("? NOT DEFINED\n");
            }
            break;
        case 'l':
        case 'L':
            if (op_1 > 0)
            {
                result = log(op_1);
                switch (precision)
                {
                case 0:
                    printf("LOG(%.f) = %.f\n", op_1, result);
                    break;
                case 1:
                    printf("LOG(%.1f) = %.1f\n", op_1, result);
                    break;
                case 3:
                    printf("LOG(%.3f) = %.3f\n", op_1, result);
                    break;
                default:
                    printf("LOG(%G) = %G\n", op_1, result);
                    break;
                }
            } else
            {
                printf("? COMPLEX LOG\n");
            }
            break;
        case '.':
            printf("ANS DISCARDED.\n");
            op1query = 1;
            break;
        case 'Q':
        case 'q':
            exitflag = 1;
            break;
        case 'R':
        case 'r':
            precision = inputrestricted("SIGN.DIGITS [0,1,3]: ", " %[013]") - 0X30;
            printf("ROUNDED %G", result);
            result = rounddouble(result, precision);
            printf("-> %G\n", result);
            break;
        default:
            printf("? ERROR, UNFORSEEN CASE.\n");
            return -1;
            break;
        }
        if (op1query)
        {
            op_1 = inputdouble("#: ");
        } else
        {
            op_1 = result;
        }
        op1query = 0;
    }
    return 0;
}