C++ Program to Find Largest of Two Numbers

In this article, you will learn and get code to find and print largest of given two numbers by user at run-time in C++. Here are the list of approaches used to create the program:

• Find largest of two numbers using if-else
• using conditional operator
• using user-defined function
• using class and object

Find Largest of Two Numbers using if-else

To find the largest between two numbers in C++ programming, you have to ask from user to enter any two numbers. Now use if-else statement to find the largest. And then print the largest as shown in the program given below.

The question is, write a program in C++ to find largest/gretest of two numbers. Here is its answer:

#include<iostream>
using namespace std;
int main()
{
    int numOne, numTwo, larg;
    cout<<"Enter the Two Numbers: ";
    cin>>numOne>>numTwo;
    if(numOne>numTwo)
        larg = numOne;
    else
        larg = numTwo;
    cout<<"\nLargest = "<<larg;
    cout<<endl;
    return 0;
}

This program was build and run under Code::Blocks IDE. Here is its sample run:

Now supply any two numbers say 5 and 6. Press ENTER key to find and print the largest one as shown in the snapshot given below:

Here is another sample run with user input, 6 (as first) and 5 (as second number):

In above program, using if-else, we've compared the value of numOne (first number) with numTwo (second number). That is, if numOne's value is greater than numTwo's, then the value of numOne gets initialized to larg. Otherwise the value of numTwo gets initialized to larg

Logically, when user enters the two number say 5 and 6 in same order. That is, 5 as first and 6 as second number. Then 5 gets stored in numOne and 6 gets stored in numTwo

Now the condition of if gets evaluated. That is, the condition, numOne>numTwo or 5>6 evaluates to be false, therefore program flow does not goes inside if's body. Rather it goes to its else's part. And the value of numTwo (6) gets initialized to larg

Finally just print the value of larg on output, that will be the largest number on your screen.

Find Largest of Two Numbers using Conditional Operator

Here is another C++ program that also find and prints the largest between given two numbers, but using conditional operator (?:).

#include<iostream>
using namespace std;
int main()
{
    int numOne, numTwo, larg;
    cout<<"Enter the Two Numbers: ";
    cin>>numOne>>numTwo;
    larg = (numOne>numTwo) ? numOne : numTwo;
    cout<<"\nLargest = "<<larg;
    cout<<endl;
    return 0;
}

This program produces the same output as of previous program. In this program, the following code:

(numOne>numTwo) ? numOne : numTwo

states that, if the value of numOne is greater than the value of numTwo, then whole expression becomes numOne. Otherwise whole expression becomes numTwo.

That is, if the condition, numOne>numTwo, of conditional operator (?:) evaluates to be true, then the value of numOne gets initialized to larg. Otherwise the value of numTwo gets initialized to larg

Find Largest of Two Numbers using Function

Let's create another C++ program using a user-defined function, largeOfTwo() to find largest of two numbers.

The function, largeOfTwo() takes two numbers as its argument, and returns the largest from its both arguments.

#include<iostream>
using namespace std;
int largeOfTwo(int, int);
int main()
{
    int numOne, numTwo, larg;
    cout<<"Enter the Two Numbers: ";
    cin>>numOne>>numTwo;
    larg = largeOfTwo(numOne, numTwo);
    cout<<"\nLargest = "<<larg;
    cout<<endl;
    return 0;
}
int largeOfTwo(int nOne, int nTwo)
{
    if(nOne>nTwo)
        return nOne;
    else
        return nTwo;
}

Find Largest of Two Numbers using Class and Object

This is the last program of this article, that does the same job as of previous programs. The only difference is, this program uses class and object feature of C++ to find and print largest or greatest of two entered numbers by user.

#include<iostream>
using namespace std;
class CodesCracker
{
    public:
        int findLargest(int, int);
};
int CodesCracker::findLargest(int a, int b)
{
    if(a>b)
        return a;
    else
        return b;
}
int main()
{
    CodesCracker c;
    int numOne, numTwo, larg;
    cout<<"Enter the Two Numbers: ";
    cin>>numOne>>numTwo;
    larg = c.findLargest(numOne, numTwo);
    cout<<"\nLargest = "<<larg;
    cout<<endl;
    return 0;
}

Inside the main() function, an object c of type CodesCracker is created. And using this object, we've called the function findLargest() of the class CodesCracker.

Same Program in Other Languages

• C Find Largest of two Numbers
• Java Find Largest of two Numbers
• Python Find Largest of two Numbers

C++ Online Test