Function Overloading

Video Summary: https://youtu.be/xOVD3MIwES4

As you have seen, when you make a call to a function, you have to specify the datatype for the parameters (the input into the function) and the return (the output out of the function). However, sometimes you might want to accept multiple types of data, such as a sum function that can add two integers, an integer and a float, or two floats.

One way of handling this is to make multiple functions with the same name that take and return different datatypes. The compiler will automatically determine which function it should call based on which function call matches the input. This is called function overloading.

Consider the following example that takes a string input. It checks if there is a decimal and either converts it to an int or a float, then uses overloaded functions to output the type:

Exercise

For this exercise, you will create an overloaded sum function that will add either two integers or two floats together. For the sake of simplicity, you may assume that the inputs will always match (two integers or two floats, not one integer one float).

Take two string inputs
Determine if they are integers or floats
Create an overloaded sum function to add them together
Use the overloaded function to add the two inputs together

Solution

/*
Program name: overload.cpp
Author: Devon Blewett
Purpose: This program takes two string inputs, and checks the first one for a decimal.  If it contains one, it converts the strings to floats and adds them.  Otherwise it converts the strings to integers and adds them.

Written for the Open Textbooks program
*/
#include <iostream>
using namespace std;

// overloaded function prototype sum
void sum(int n1, int n2);
void sum(float n1, float n2);

int main()
{
    // variables to store the inputs and numbers
    string input1;
    string input2;
    int intResult1;
    int intResult2;
    float floatResult1;
    float floatResult2;
    // prompt the user for two numbers
    cout << "Enter 2 numbers: " << endl;
    cin >> input1;
    cin >> input2;
    // check if the first number is a float
    if(input1.find(".") != string::npos){
        // convert strings to float
        floatResult1 = stof(input1);
        floatResult2 = stof(input2);
        // add two float numbers
        sum(floatResult1, floatResult2);
    }
    else{
        // conver strings to int
        intResult1 = stoi(input1);
        intResult2 = stoi(input2);
        // add two int numbers
        sum(intResult1, intResult2);
        }
}
// overloaded function definitions for sum
void sum(int n1, int n2){
    cout << n1 << " + " << n2 << " is " << n1 + n2 << endl;
}

void sum(float n1, float n2){
    cout << n1 << " + " << n2 << " is " << n1 + n2 << endl;
}

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