c - 如何检查c中是否有除零

Question

#include<stdio.h>
void function(int);

int main()
{
     int x;

     printf("Enter x:");
     scanf("%d", &x);

function(x);

return 0;
}

void function(int x)
{
    float fx;

    fx=10/x;

    if(10 is divided by zero)// I dont know what to put here please help
        printf("division by zero is not allowed");
    else
        printf("f(x) is: %.5f",fx);

}

Answer 1

#include<stdio.h>
void function(int);

int main()
{
     int x;

     printf("Enter x:");
     scanf("%d", &x);

function(x);

return 0;
}

void function(int x)
{
    float fx;

    if(x==0) // Simple!
        printf("division by zero is not allowed");
    else
        fx=10/x;            
        printf("f(x) is: %.5f",fx);

}

Answer 2

这应该这样做。在执行除法之前，您需要检查是否被零除。

void function(int x)
{
    float fx;

    if(x == 0) {
        printf("division by zero is not allowed");
    } else {
        fx = 10/x;
        printf("f(x) is: %.5f",fx);
    }
}

Answer 3

默认情况下，在 UNIX 中，浮点除以零不会因异常而停止程序。相反，它产生的结果是infinityor NaN。您可以使用isfinite.

x = y / z; // assuming y or z is floating-point
if ( ! isfinite( x ) ) cerr << "invalid result from division" << endl;

或者，您可以检查除数是否不为零：

if ( z == 0 || ! isfinite( z ) ) cerr << "invalid divisor to division" << endl;
x = y / z;

Answer 4

使用 C99，您可以使用fetestexcept(2)等。