C++ Program to Find the Largest of Three Numbers

This article will teach you how to use C++ to find and print the largest of three numbers entered by the user at run-time. The program is created in the following ways:

Both programs uses if-else to find and print the largest or biggest among any three numbers entered by the user.

In C++, find the largest of three numbers

To find the largest number among three numbers in C++ programming, you have to ask the user to enter the three numbers. Now use the if-else ladder to find out which of the three is the largest, as shown in the program given below:

The question is, "Write a program in C++ that finds the largest of three numbers." Here is its answer:

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

This program was built and runs under the Code::Blocks IDE. Here is its sample run:

C++ program find biggest of three

Now supply any three numbers as input, say 1, 2, and 3. The third number is the largest in this case, and the second number is the second-largest. Press the ENTER key to print the largest of these three numbers, as shown in the output given below:

C++ program find largest of three

Here is another sample run with user inputs 1, 3, and 2. The second number is the largest in this case, and the third number is the second largest:

C++ program find largest in three

Here is one more sample run with user input: 3, 1, 2:

find largest of three numbers c++

Main Logic of the Previous Program

The main logic behind the code is:

The previous program is demonstrated with a dry run

The dry run of the above program with user inputs 2, 1, and 3 goes like this:

Using a C++ function, find the largest of three numbers

This program does the same job as the previous program. But internally, this program uses a different approach to do the task. That is, this program is created using a user-defined function, findLargest().

The function findLargest() takes three numbers as its arguments and returns the largest among them. So the largest number gets returned by this function and initialized to larg inside the main() function. Therefore, just print the value of larg.

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

This program produces the same output as the previous program.

The same program in different languages

C++ Quiz


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