The fmod Function in C & C++

More functions from the  <math.h> or <cmath> header files. Today it’s about the fmod function.

The modulus operator, %, returns the remainder of a over b. For example, 5 % 2 = 1 since 4, a multiple of 2, plus 1, the remainder, equals 5. The modulus operator however can only be used with whole numbers. The fmod function applies the same principle to floating-point numbers.

 

From C11 standard.

 

Test Code.

I tested the functions in Visual C++ 2010 as an console application.

// The standard library includes the system function.

#include <cstdlib>

// C++ standard I/O library.

#include <cstdio>

// C++ math library.

#include <cmath>

int main()

{

     // Header.

     printf("fmod Function\n\n");

     printf("x = fmod(a,b) \n\n\n");

     printf("Integer Modulus\n");

     printf("5 %% 2 = %d", 5 % 2);

     printf("\n\nFloating-point Modulus\n");

     printf("modf(5.3, 2) = %6.3f\t", fmod(5.3, 2.0));

     printf("\n\n");    

     // Keep console window open.

     system("pause");

     // Return some value.

     return 0;

} // end main

Output.