C++ Program to Find Largest Among Three Numbers

Here, we will see how to find the largest among three numbers using a C++ program. Below are the examples:

Input: a = 1, b = 2, c = 45
Output: The Largest Among 3 is 45

Input: a = 75, b = 134, c = 9
Output: The Largest Among 3 is 134

There are 3 ways to find the largest among the three numbers in C++:

1. Using If-else Statement.
2. Using Logical Operators.
3. Using Ternary Operator.

Let’s start discussing each of these methods in detail.

1. Using If-else Statement

The following algorithm will be used here:

Algorithm:

1. Start.
2. Input a, b and c.
3. Check the condition a>=b
4. If step 3 is True go to step 5 else go to step 9.
5. Check the condition a>=c.
6. If step 5 is True go to step 7 else go to step 8.
7. Print “The Largest Among 3 is: a and go to step 13
8. Print “The Largest Among 3 is: c and go to step 13.
9. Check the condition b>=c.
10. If step 9 is True go to step 11 else go to step 12.
11. Print “The Largest Among 3 is: b and go to step 13.
12. Print “The Largest Among 3 is: c and go to step 13.
13. Stop.

Flowchart:

Below is the C++ program to find the largest among three numbers using the if-else statement:

C++

// C++ Program to Find Largest Among
// Three Numbers Using if-else
// Statement
#include<bits/stdc++.h>
using namespace std;

// Driver code
int main()
{
  int a, b, c;
  cout << "Enter the three numbers a, b & c" <<
           endl;
  cin >> a >> b >> c;

  if(a >= b)
  {
    if(a >= c)
    {
      cout << "The Largest Among Three Numbers is : " <<
               a << endl;
    }
    else
    {
      cout << "The Largest Among Three Numbers is : " <<
               c << endl;
    }
  }
  else
  {
    if(b >= c)
    {
      cout << "The Largest Among Three Numbers is : " <<
               b << endl;
    }
    else
    {
      cout << "The Largest Among Three Numbers is : " <<
               c << endl;
    }
  }
  return 0;
}

Output:

Time Complexity: O(1)
Auxiliary Space: O(1)

2. Using Logical Operator

Below is the flowchart for finding the largest number using the logical operator:

Below is the C++ program to find the largest among three numbers using the logical operator:

C++

// C++ program to find largest
// among three numbers using
// logical operator
#include<bits/stdc++.h>
using namespace std;

// Driver code
int main()
{
    int a, b, c;
    cout << "Enter the three numbers a, b & c" <<
             endl;
    cin >> a >> b >> c;

    if(a >= b && a >= c)
    {
        cout << "The Largest Among Three Numbers is : " <<
                 a << endl;
    }
    else if(b >= a && b >= c)
    {
        cout << "The Largest Among Three Numbers is : " <<
                 b << endl;
    }
    else
    {
        cout << "The Largest Among Three Numbers is : " <<
                 c << endl;
    }

    return 0;
}

Output:

Time Complexity: O(1)
Auxiliary Space: O(1)

3. Using Ternary Operator

Below is the C++ program to find the largest among the three numbers using the ternary operator:

C++

// C++ program to find largest
// among three numbers using
// ternary operator
#include<bits/stdc++.h>
using namespace std;

// Driver code
int main()
{
    int a, b, c, ans;
    cout << "Enter the three numbers a, b & c" <<
             endl;
    cin >> a >> b >> c;

    ans = (a >= b ? (a >= c ? a : c) :
          (b >= c ? b : c));
    cout << "The Largest Among Three Numbers is : " <<
             ans << endl;
    return 0;
}

Output:

Time Complexity: O(1)
Auxiliary Space: O(1)