C++ Overloading Functions

[qingquan-li]

Concept: Two or more functions may have the same name, as long as their parameter lists are different.

Recall that a class can have more than one constructor, but all constructors of a class have the same name (but different set of parameters), which is the name of the class. This case is an example of overloading a function.

Example 1 of 2

// This program uses overloaded functions.

#include <iostream>
using namespace std;

float average(float, float);
float average(float, float, float);

int main() {
    cout << average(0.1, 0.2, 0.3) << endl; // 0.2
    cout << average(4.0, 5.0) << endl;            // 4.5
    return 0;
}

float average(float num1, float num2) {
    return (num1 + num2) / 2;
}

// Overload function average:
float average(float num1, float num2, float num3) {
    return (num1 + num2 + num3) / 3;
}

Example 2 of 2

// This program uses overloaded functions.

#include <iostream>
using namespace std;

// Function prototypes
int square(int);
double square(double );

int main() {
    cout << square(12) << endl;     // 144
    cout << square(3.1415) << endl; // 9.86902
    return 0;
}

int square(int number) {
    return number * number;
}

//*************************************************
// Definition of overloaded function square.      *
// This function uses a double parameter, number. *
// It returns the square of number as a double.   *
//*************************************************

double square(double number) {
    return number * number;
}