C++ Program to Find Largest Number Among Three Numbers

To understand this example, you should have the knowledge of the following C++ programming topics:

In this program, the user is asked to enter three numbers.

Then this program finds out the largest number among three numbers entered by user and displays it with a proper message.

This program can be written in more than one way.

Example 1: Find Largest Number Using if...else Statement

``````#include <iostream>
using namespace std;

int main() {

double n1, n2, n3;

cout << "Enter three numbers: ";
cin >> n1 >> n2 >> n3;

// check if n1 is the largest number
if(n1 >= n2 && n1 >= n3)
cout << "Largest number: " << n1;

// check if n2 is the largest number
else if(n2 >= n1 && n2 >= n3)
cout << "Largest number: " << n2;

// if neither n1 nor n2 are the largest, n3 is the largest
else
cout << "Largest number: " << n3;

return 0;
}``````

Output

```Enter three numbers: 2.3
8.3
-4.2
Largest number: 8.3```

Example 2: Find the Largest Number Using Nested if...else statement

``````#include <iostream>
using namespace std;

int main() {

double n1, n2, n3;

cout << "Enter three numbers: ";
cin >> n1 >> n2 >> n3;

// check if n1 is greater than n2
if (n1 >= n2) {

// if n1 is also greater than n3,
// then n1 is the largest number
if (n1 >= n3)
cout << "Largest number: " << n1;

// but if n1 is less than n3
// but n1 is greater than n2
// then n3 is the largest number
else
cout << "Largest number: " << n3;
}

// else, n2 is greater than n1
else {

// if n2 is also greater than n3,
// then n2 is the largest number
if (n2 >= n3)
cout << "Largest number: " << n2;

// but if n2 is less than n3
// but n2 is greater than n1
// then n3 is the largest number
else
cout << "Largest number: " << n3;
}

return 0;
}``````

Output

```Enter three numbers: 2.3
8.3
-4.2
Largest number: 8.3```

• For example, with `num1 = 12` and `num2 = 8`, the return value should be 12.