#include <stdio.h>


int CalcAll()
{
    int number1,number2;
    char op,ch;
    char str[100];

    FILE *f;
    f=fopen("Exp.txt","w");
    if(f==NULL)
    {
        printf("Failed open");
        return 0;
    }
    fputs("12+4=",f);
    fputs("15+7",f);
    fclose(f);

    f=fopen("Exp.txt","r");
    if(f==NULL)
    {
        printf("Falied open");
        return 0;

    }
    fgets(str,100,f);

    while(!feof(f))
    {
        printf("%f",CalcExp(str));
        fgets(str,100,f);
    }

    fclose(f);


}




float CalcExp(char* str)
{
int counter=0,i,Sum=0,Sum2=0;
char P;
float answer;

for(i=0;str[i]!='=';i++)
{
if('0'<=str[i]&&str[i]<='9')
{
if(counter==2)
{
Sum=0;
counter=3;
}

Sum=Sum*10;
Sum=Sum+str[i]-'0';

}
if(str[i]==' ')
{
    Sum2=Sum;
    counter++;
}
if(str[i]=='*'||str[i]=='+'||str[i]=='-'||str[i]=='/')
P=str[i];

}

switch(P)
{
case '+':
answer=Sum2+Sum;
break;

case '-':
answer=Sum2-Sum;
break;

case '*':
answer=Sum2*Sum;
break;

case '/':
answer=(float)Sum2/Sum;
break;
}

return answer;
}

void main()
{
    int answer;

    answer=CalcAll();
}