Day 3: Functions

Why define your own functions?

• Readability
• Maintainability
• Code reuse

#include <iostream>
using namespace std;
int raiseToPower(int base, int exponent) {
  int result = 1;
  for (int i = 0; i < exponent; i = i + 1) {
    result = result * base;
  }
  return result;
}
int main() {
  int threeExpFour = raiseToPower(3, 4);
  cout << "3^4 is " << threeExpFour << endl;
  return 0;
}

 

 

Function delaration should be be set before function invocation.

 

Returning a value

 

• Up to one value may be returned
• Must be the same type as the return type
• No need to be at the end
• Returns the value as soon as a return statement is executed

Fucntion overloading

void printOnNewLine(int x)
{
    cout << "1 Integer: " << x << endl;
}
void printOnNewLine(int x, int y)
{
    cout << "2 Integers: " << x << " and " << y << endl;
}

 

Function prototypes are generally put into separate header files.

Recursion

• Functions can call themselves
• base case
• recursive step

Pass by value(a) vs pass by reference(&a)