Default Arguments in C++ Function


Definition

The default argument is an assigned value in the function declaration. That value will be assigned by the compiler when function call doesn't have that argument.

Syntax

return_type function_name( param_1,param_2 = value )
for example,
int fn_multipy(int x, int y = 1);

Default Arguments in Function Example Program

//Simple Default Argument Function Example Program in C++
//Function Example

#include<iostream>
#include<conio.h>

using namespace std;

int fn_multipy(int x, int y = 1);

int main() {
   int a = 200, b = 100;
   cout << "Simple Default Argument Function Example Program\n";

   cout << "\nWorks for a and b    :" << fn_multipy(a, b);
   cout << "\nWorks for a          :" << fn_multipy(a);

   getch();
}

// Default Argument Function

int fn_multipy(int x, int y) {
   return (x * y);
}

Sample Output

Simple Default Argument Function Example Program

Works for a and b    :20000
Works for a          :200