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C Standard Library <ctype.h> C Standard Library <assert.h>

C Library Macro assert()

C Standard Library - <assert.h>

C Library Macro void assert(int expression) It allows diagnostic information to be written to the standard error file. In other words, it can be used to add diagnostics to C programs.

Declaration

Below is the declaration of the assert() macro.

void assert(int expression);

Parameter

expression -- 　this can be a variable or any C expression. If expression If TRUE, assert() does not perform any action. If expression If FALSE, assert() will display an error message on standard error stderr and terminate the program execution.

Return Value

This macro does not return any value.

Online Example

The following example demonstrates the usage of the assert() macro.

Example

#include <assert.h>
#include <stdio.h>
　
int main()
{
　　　int a;
　　　char str[50];
　　　　　
　　　printf("Please input an integer value: \t");
　　　scanf("%d", &a);
　　　assert(a >=　10);
　　　printf("The input integer is: \t%d\n", a);
　　　　
　　　printf("Please input a string: \t");
　　　scanf("%s", str);
　　　assert(str != NULL);
　　　printf("The input string is: \t%s\n", str);
　　　　
　　　return(0);
}

Let's compile and run the above program in interactive mode as follows:

Please enter an integer value:　23
The input integer is:　23
Please enter a string:　w3codebox　
The input string is:　w3codebox

C Standard Library - <assert.h>

C Standard Library <ctype.h> C Standard Library <assert.h>