C++ Function Overloading

Function Overloading

Function overloading allows multiple functions to have the same name, as long as their parameters are different in type or number:

Example

  int myFunction(int x)
float myFunction(float x)
double
  myFunction(double x, double y)

This lets you use the same function name for similar tasks.

Without Function Overloading

Consider the following example, which have two functions that add numbers of different type:

Example

int plusFuncInt(int x, int y) {
  return x + y;
}

double plusFuncDouble(double x, double y) {

return x + y;
}

int main() {
  int myNum1 = plusFuncInt(8,
5);
  double myNum2 = plusFuncDouble(4.3, 6.26);

  cout <<
"Int: " << myNum1 << "\n";
  cout << "Double: " << myNum2;

return 0;
}

Problem: We had to create two different function names for the same logic.

Using Function Overloading

Instead of defining two functions that should do the same thing, it is better to overload one.

In the example below, we overload the plusFunc function to work for both int and double:

Example

int plusFunc(int x, int
y) {
  return x + y;
}

double plusFunc(double x, double y) {

return x + y;
}

int main() {
  int myNum1 = plusFunc(8,
5);
  double myNum2 = plusFunc(4.3, 6.26);

  cout << "Int: " <<
myNum1 << "\n";
  cout << "Double: " << myNum2;
  return 0;
}

Note: Multiple functions can have the same name as long as the number and/or type of parameters are different.

Function Overloading by Number of Parameters

In this example, we overload a function by using a different number of parameters:

Example

int plusFunc(int x, int y) {
  return x + y;
}

int plusFunc(int x, int y, int z) {
  return x + y + z;
}

int main() {
  int result1 = plusFunc(3, 7);
  int result2 = plusFunc(1, 2, 3);

  cout << "Sum of 2 numbers: " << result1 << "\n";
  cout << "Sum of 3 numbers: " << result2;
  return 0;
}