Thread: Code help!!

So i wrote out a snippet of my code for a program that is supposed to add and later simplify two fractions. To check if the first part of my program was working, I ran a side program with this code:

Code:

#include <stdio.h>
#include <stdlib.h>


int main()
{
    int a, b, c, e, num, first, second, den, whole, newnum, t;
        
    do
    {
        printf(">> ");
        scanf("%d/%d + %d/%d", &a, &b, &c, &d);
        if((b==0)||(d=0))
        {
            printf("Invalid input: Denominator cannot be zero!");
        }
        if ((b!=0)&&(d=!0))
        {
            break;
        }
    }
    while((b==0)||(d==0));
    if(b<0)
    {
        a=-a;
        b=abs(b);
    }
    if(d<0)
    {
        c=-c;
        d=abs(d);
    }
    printf("%d %d %d %d\n", a, b, c, d);
    first=a*d;
    second=b*c;
    num=first+second;
    den=b*d;
    printf("%d %d %d %d\n", first, second, num, den);
    return 0;
}

I printed out values for a b c and d to make sure the computer was getting the correct values from the user. The user's input is supposed to be in this form: a/b + c/d wherein a b c and d are provided by the user. For some reason, whatever is inputted in the d variable, the program still prints out 1 for the d variable. The other variables are fine. Because the d always comes out as 1, then the corresponding variables that rely on what d is come out wrong.

Please help! I cant seem to locate the problem. Here is a snippet of what happens when i run this program

Originally Posted by haroldco

So i wrote out a snippet of my code for a program that is supposed to add and later simplify two fractions. To check if the first part of my program was working, I ran a side program with this code:

Code:

#include <stdio.h>
    do
    {
        printf(">> ");
        scanf("%d/%d + %d/%d", &a, &b, &c, &d);
        if((b==0)||(d=0)) // <-- d = 0
        {
            printf("Invalid input: Denominator cannot be zero!");
        }
        if ((b!=0)&&(d=!0)) // <-- d = !0
        {
            break;
        }
    }

You don't need that second if statement. But your problem is that you assign 0 to d in the first if statement.

In the second statement you assign !0 to d meaning 1.

For a start, correct me if I'm just blind but where did you declare d?

when i always get stuck i print out a hello from all the loops and methods etc.

i did that with your code, Im only a beginner and i don't really use c much but this shows where your value for d is being changed to '0'

d = the correct input until it reaches the second if statement with the break inside:

Code:

 scanf("%d%d%d%d", &a, &b, &c, &d);
printf("%d %d %d %d\n", a, b, c, d);
if((b==0)||(d==0))
{
printf("Invalid input: Denominator cannot be zero!");
}
printf("%d %d %d %d\n", a, b, c, d);
if ((b!=0)&&(d=!0))
{
break;
}
printf("%d %d %d %d\n", a, b, c, d);