Functions
C++ functions work like C's, but add two powerful features: default arguments (a parameter can have a fallback value) and function overloading (multiple functions can share a name if their parameter lists differ).
💡 Key insight
Function overloading lets add(int,int) and add(double,double) coexist — the compiler picks the right one based on the arguments.
Syntax
syntax
returnType functionName(type param = defaultValue) {
return value;
}Example
Both functions are named add; the compiler chooses which one to call based on the argument types.
cpp
#include <iostream>
using namespace std;
int add(int a, int b) {
return a + b;
}
double add(double a, double b) {
return a + b;
}
int main() {
cout << add(2, 3) << endl;
cout << add(2.5, 3.5) << endl;
return 0;
}output5
6
Try it yourself
Copy this example into the C++ compiler and run it — try changing a value and see what happens.