C Program to Handle Divide By Zero and Multiple Exceptions

In C programming, there is no built-in exception handling like in other high-level languages such as C++, Java, or Python. However, you can still handle exceptions using error checking, function return values, or by using signal handlers. In this answer, we’ll discuss two methods for handling exceptions in C, particularly handling divide-by-zero errors.

Methods to Handle Divide by Zero and Multiple Exceptions

There are 2 methods to handle divide-by-zero exceptions mentioned below:

• Error checking and function return values
• Signal handling

1. Error checking and function return values

In this method, we use return values of functions to indicate if an error has occurred. We can write a custom function that checks for divide-by-zero exceptions and returns an error code if it occurs.

Example:

C

// C Program to handle divide-by-zero exceptions using
// error checking
#include <stdbool.h>
#include <stdio.h>

bool safe_divide(double num, double denom, double* result)
{
    if (denom == 0) {
        return false;
    }
    *result = num / denom;
    return true;
}

// main function
int main()
{
    double numerator, denominator, quotient;

    // Taking input
    printf("Enter numerator: ");
    scanf("%lf", &numerator);

    printf("Enter denominator: ");
    scanf("%lf", &denominator);

    // handling exceptions using in-build function
    if (safe_divide(numerator, denominator, "ient)) {
        printf("The quotient is: %.2lf\n", quotient);
    }
    else {
        printf("Error: Division by zero is not allowed.\n");
    }

    return 0;
}

Output:

Enter numerator: 10
Enter denominator: 0
Error: Division by zero is not allowed.

2. Signal handling

Signal handling can be used to catch hardware exceptions like divide-by-zero errors. When a signal is raised, the program jumps to a specified signal handling function. by using the feclearexcept and fetestexcept functions from the fenv.h header. This version checks for floating-point exceptions explicitly and handles them accordingly.

Example:

C

// C Program to demonstrate use of signal handlinng
#include <fenv.h>
#include <setjmp.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>

jmp_buf recovery;

void handle_divide_by_zero(int sig)
{
    // Re-assign the signal handler
    signal(SIGFPE, handle_divide_by_zero);
    printf("Error: Division by zero is not allowed.\n");
    // Jump to the recovery point
    longjmp(recovery, 1);
}

// main function
int main()
{
    double numerator, denominator, quotient;
    int recovery_status;

    // Assign the signal handler
    signal(SIGFPE, handle_divide_by_zero);

    printf("Enter numerator: ");
    scanf("%lf", &numerator);
    printf("Enter denominator: ");
    scanf("%lf", &denominator);

    // Set a recovery point
    recovery_status = setjmp(recovery);

    if (recovery_status == 0) {

        // Clear all floating-point exceptions
        feclearexcept(FE_ALL_EXCEPT);
        quotient = numerator / denominator;

        // Test for the divide-by-zero exception
        if (fetestexcept(FE_DIVBYZERO)) {
            // Raise the SIGFPE signal
            raise(SIGFPE);
        }
        else {
            printf("The quotient is: %.2lf\n", quotient);
        }
    }

    return 0;
}

Output:

Enter numerator: 10
Enter denominator: 0
Error: Division by zero is not allowed.