C语言中分数简化程序的浮点异常

Question

When I run the following code, I always get a floating-point exception. How can I fix it?

    #include <stdio.h>

    //Global Variables

    int num, denom, num1, denom1;

    void simplify(int *numerator, int *denominator);

    int main () {

    //Prompt User as to what program is
    printf("Fraction Simplifier\n");
    printf("===================\n");

    //Ask User for Numerator and Denominator
    printf("Numerator: ");
    scanf("%d", &num);
    printf("Denominator: ");
    scanf("%d", &denom);

    //Call Function
    simplify(&num1, &denom1);

    //Display final output
    printf("%d / %d = %d / %d", num, denom, num1, denom1);

    return 0;
    }

    //Simplify function
    void simplify(int *numerator, int *denominator)
    {

    num = num1;
    denom = denom1;

    num1 = num1 / num1;
    denom1 = denom1 / num1;
    num1 = *numerator;
    denom1 = *denominator;

    }

Answer 1

It looks as if num1 is never initialized. It will be zero, which will result in a division by zero.

Answer 2

Your simplify function is flawed. Here's what it means when you are calling simplify :

call simplify, passing the address of num1 and denom1

And here's what your code inside of simplify means:

num = num1;          /* Assign the value of num1 to num, meaning set num to 0. */
denom = denom1;      /* Assign the value of denom1 to denom, meaning set denom to 0. */
num1 = num1 / num1;  /* Divide num1 (which is 0) by num1 (which is 0). Error! */

You can simplify your program and make it easier to understand by eliminating your global variables. This will also help you to correct your errors. Here's a rewrite:

#include <stdio.h>

void simplify(int numerator, int denominator, int* newNumerator, int* newDenominator);

int main () {

    int num, denom, num1, denom1;

    /* Do your input code */

    //Call Function
    simplify(num, denom, &num1, &denom1);

    //Display final output
    printf("%d / %d = %d / %d", num, denom, num1, denom1);

    return 0;
}

//Simplify function
void simplify(int numerator, int denominator, int* newNumerator, int* newDenominator)
{
    int simplifiedNumerator;
    int simplifiedDenominator;

    /* Calculate your results.. left out your original code, which calculates incorrectly */
    /* You will refer to the ints numerator and denominator */

    /* Assign your results */
    *newNumerator = simplifiedNumerator;
    *newDenominator = simplifiedDenominator;
}

Notice that simplify now has four parameters. The first two are the values you want to use in the calculation (we don't need pointers), and the pointers are only used to assign the results to the addresses passed in.