#include <stdio.h>
#include <string.h>
#include <malloc.h>
#define STACK struct stack
#define STACK_M struct stack_m

const  char *filenameout = "out.txt";
const  char *filenamein = "in.txt";

void writefile(const char* filename, char* content) // записывает в файл filename content
{
    FILE *fout;
    fout = fopen(filename, "a");
    if (fout == NULL)
	{
        printf("file %s not opened",filenameout );
	    return ;
	}
	if (content == "")
	    fprintf(fout,"%s",content);
	else
	{
	    fprintf(fout,"%s\n",content);
        fclose(fout);
	}
}

int Checksintax(char* code) // проверка на синтаксические ошибки
{
    if (code == NULL)
        return - 21;
    int flag1 = 0, i = 0, k = 0, j1 = 0, j2 = 0, len = strlen(code);
    for(i=0;i<len;i++)
    {
        if ((code[i]>='0')&&(code[i]<='9'))
            j1++;

        if ((code[i] == '+')||(code[i] == '-')||(code[i] == '*')||(code[i] == '/'))
        {
            if(i == len-1)
                return -8;
            j2++;
        }
        if (code[i]=='(')
        {
            k++;
            if (code[i+1] == ')')
                return -5;
        }
        if (code[i]==')')
        {
            k--;
            if (code[i+1] == '(')
                return -9;
        }
        if (code[i]=='.')
            return -1;
        if (code[i]==' ')
            return -13;
        if ((code[i]>=65)&&(code[i]<=90))
        {
            flag1++;
            return -3;
        }
        if ((code[i]>=97)&&(code[i]<=122))
        {
            flag1++;
            return -4;
        }
    }
    if(flag1 > 0)
        return -20;
    if (j1 < j2+1)
        if (j2 != 0)
	        return -65;
    if (k != 0)
        return -2;
    return 0;
}

void writefileint(const char* filename, int content) // вывод результата
{
        FILE *fout;
        fout = fopen(filename, "w");
        if (fout == NULL)
    	{
    	    printf("file %s not opened",filename);
    	    return ;
    	}
        fprintf(fout," %d",content);
	   	fclose(fout);
}

STACK_M // лист содержащий указатель на голову стека
{
    STACK* head;
};

STACK // стэк
{
    char data;
    STACK* next;
};

void push(STACK_M* A, char *b) // новые эелменты стека
{
    STACK* B;
    B = (STACK*)malloc(sizeof(STACK*));
    B->data = *b;
    B->next = A->head;
    A->head = B;
}
int tabl(char a) //приоритеты знаков
{
    int b = -2;
    if (a == '(')
        b = 0;
    if (a == ')')
        b = 1;
    if ((a == '+')||(a == '-'))
        b = 2;
    if ((a == '*')||(a == '/'))
        b = 3;
    if (a == '^')
        b = 4;
    return b;
}

void pop(STACK_M* A, char *b) // достаем значение из головы стека
{
    STACK* B;
    B = A->head;
    *b = A->head->data;
    if (A->head->next)
        A->head = A->head->next;
    else
        A->head = NULL;
    free(B);
}

void show(STACK_M* A) // выводит стек ( для отладки)
{
    STACK* cur;
    cur = A->head;
    int i = 0;
    while(cur)
    {
        printf("\n data[%d] = %c",i,cur->data);
        cur = cur->next;
        i++;
    }
    printf("\n");
}

char* charcat(char* code, char data) //аналог "strcat" только к строке добавляется 1 символ и пробел
{
    int len = strlen(code);
    code[len]=data;
    code[len+1] = ' ';
    code[len+2] = '\0';
    return code;
}

int tablstack(STACK_M*A) // приоритет знакак в стеке
{
    STACK* cur;
    cur = A->head;
    char a;
    a = cur -> data;
    int tab;
    tab = tabl(a);
    return tab;
}

int calc(char* code, int N,int* flag) // калькулятор
{
    char* tmp;
    tmp = (char*)malloc(N*sizeof(char*));
    tmp[0] = '\0';
    int count = 0;
    int* stak;
    stak = (int*)malloc(N*sizeof(int*));
    int i = 0;
    int count11 = 0;
    int len = strlen(code);
    for (;;)
    {
        if ((code[i]>='0')&&(code[i]<='9'))
        {
            int g = 0;
            while (code[i]!=' ')
            {
                tmp[g] = code[i];
                tmp[g+1]='\0';
                g++;
                i++;
            }
            int celo = atoi(tmp);
            stak[count11] = celo;
            tmp[0]='\0';
            count11++;
        }
        else
        {
            if (code[i]=='+')
            {
                stak[count11-2]=stak[count11-1]+stak[count11-2];
                count11--;
            }
            if (code[i]=='-')
            {
                stak[count11-2]=stak[count11-2]-stak[count11-1];
                count11--;
            }
            if (code[i]=='*')
            {
                stak[count11-2]=stak[count11-1]*stak[count11-2];
                count11--;
            }
            if (code[i]=='/')
            {
              if (stak[count11-1] == 0)
              {
                  writefile(filenameout,"division by zero");
                  *flag = 0;
                  return -1;
              }
                stak[count11-2]=stak[count11-2]/stak[count11-1];
                count11--;
            }
            i++;
        }
        if (i == len-1 )
            break;
    }
    return stak[0];
}


int main()
{
    STACK_M* A;
    A = (STACK_M*)malloc(sizeof(STACK_M*));
    STACK* D;
    D = (STACK*)malloc(sizeof(STACK*));
    D = NULL;
    A->head = D;
    char* ex;
    ex = (char*)malloc(1000*sizeof(char*));
    ex = strcpy(ex,"");
    FILE *fin;
	fin = fopen(filenamein, "r");
	if (fin == NULL)
	{
	    printf("file not opened");
	    return -1;
	}
    char *code;
    code = (char*)malloc(2560*sizeof(char));
    if(code == NULL)
   	    return -2;
    fscanf(fin,"%[zxcvbnmasdfghjklqwertyuiopQWERTYUIOPLKJHGFDSAZXCVBNM1234567890+-*/ ().]",code);
    printf("cpde = %s\n",code);
    fclose(fin);
    int Check1;
    Check1 = Checksintax(code);
    printf("ch = %d",Check1);
    if (Check1 < 0)
    {
        writefile(filenameout,"syntax error");
        return 0;
    }
    int len = strlen(code);
    int i;
    for(i=0;i<len;i++)   // перевод в обратную польскую запись
    {
        int tab = tabl(code[i]);
        if ((code[i]>='0')&&(code[i]<='9'))
        {
            while((code[i]>='0')&&(code[i]<='9'))
            {
                ex = charcat(ex,code[i]);
                int len1 = strlen(ex);
                ex[len1-1] = '\0';
                i++;
            }
            int len1 = strlen(ex);
            ex[len1] = ' ';
            ex[len1+1] = '\0';
            i--;
        }
        if (code[i] == '(')
            push(A,&code[i]);
        if (code[i] == ')')
        {
            char b=0;
            while (b != '(')
            {
                if (A->head->data != '(')
                {
                pop(A,&b);
                ex = charcat(ex,b);
                }
                else
                    pop(A,&b);
            }
        }
        if (tab > 1)
        {
            int tab2;
            if((A->head) != NULL)
            {
                tab2 = tabl(A->head->data);
                while (tab2>=tab)
                {
                    char a;
                    pop(A,&a);
                    ex = charcat(ex,a);
                    if ((A->head) == NULL)
                        break;
                    tab2 = tabl(A->head->data);
                }
            }
            push(A,&code[i]);
        }
        if (i == len-1)
        {
            while((A->head) != NULL)
            {
                char a;
                pop(A,&a);
                ex = charcat(ex,a);
            }
            break;
        }
    }
    printf("\n ex = %s",ex);
    int res;
    int flag = 1;
    res = calc(ex,strlen(ex),&flag);
    printf("\n flag = %d",flag);
    printf("\n res = %d",res);
    if (flag == 1)
	    writefileint(filenameout,res);
    return 0;
}