Returning Function or Returning Method

Returing method is the direct opposite of void method. Returning method will return a value. In order to declare returning method , We need to use a datatype before method name and inside that method we need to use return keyword and we need to return a value. In order to understand this clearly let us study this with a code example.

NOTE
Depending on the datatype what we going to use before method name, we need to return value accordingly. If we going to use double datatype before method name that method must return a double value. If we going to use bool datatype before method name that method must return true or false. If we going to use string datatype before method name that method must return a string value.

CODE

EG 1 . Creating a returning method and trying to store inside variable, printing out in console and doing arithmetic Calculation.

#include <iostream>
using namespace std;

double DegreeToRadian(double degree);

int main() {
    //storing returning method inside a variable
    double result = DegreeToRadian(30);
    cout << result << endl;
    //printing out returning method in console
    cout << DegreeToRadian(30) << endl;
    //Arithmetic Calculation in returning method.
    cout << DegreeToRadian(30)*2/180 << endl;

    //(Ultimate goal)Assume we created DegreeToRadian method to calculate sin(30 degree)
    cout << sin(DegreeToRadian(30)) << endl;
}
double DegreeToRadian(double degree) {
    return degree * Math.PI / 180;
}

OUTPUT
0.523598
0.523598
0.00581776
0.5

CODE EXPLANATION
Try executing above codes in visual studio, There will be no errors shown since DegreeToRadian method is a returning method. Just because it is double value returning method, whenever this method is invoked depending on parameter degree value, this method is going to return radian value. All the functions what we studied as not possible in void method is possible in returning method.


Where to use void method, Where to use returning method?
I'll try to simplify this as much possible. If ultimate goal can be achieved inside our method itself we can go with void method, whereas if it cannot be achieved inside our method then we need to go with returning method.

For explaining this let us take the EG 1 what we studied above and in void function ,
We'd seen PrintRightAngleTraingleShape method as the example while studying void method. In that example our ultimate goal is to print right angle triangle shape. Our ultimate goal can be achieved inside our method itself hence we used void for PrintRightAngleTraingleShape method. whereas we used returning method above for DegreeToRadian method because here our ultimate goal is not to convert degree value to radian, it is to find sin(30 degree). In order to achieve our ultimate goal we are using DegreeToRadian as a subsidiary method to convert degree value to radian. If ultimate goal cannot be achieved and using returned value if we going to proceed our code furthur, then we need to go with returning method.

Exercises
1. Create a bool returning method with a integer parameter which returns true if argument value is a even number, returns false if argument value is a odd number.
2. Create a double returning method with a double datatype parameter to convert celsius to fahrenheit.


(Click Here, For more exercises)