Java Program to Find the Largest of three Numbers

Problem Statement: Given three numbers x, y, and z of which aim is to get the largest among these three numbers.

Example:

Input: x = 7, y = 20, z = 56
Output: 56                    // value stored in variable z

Flowchart For Largest of 3 numbers:

Algorithm to find the largest of three numbers:

1. Start
2. Read the three numbers to be compared, as A, B and C
3. Check if A is greater than B.

  3.1 If true, then check if A is greater than C
         If true, print 'A' as the greatest number
          If false, print 'C' as the greatest number

  3.2 If false, then check if B is greater than C
        If true, print 'B' as the greatest number
        If false, print 'C' as the greatest number
4. End

Approaches:

• Using Ternary operator
• Using if-else

Approach 1: Using Ternary operator

 The syntax for the conditional operator:

ans = (conditional expression) ? execute if true : execute if false

• If the condition is true then execute the statement before the colon
• If the condition is false then execute a statement after colon so

largest = z > (x>y ? x:y) ? z:((x>y) ? x:y); 

Illustration:

x = 5, y= 10, z = 3

largest  = 3>(5>10 ? 5:10) ? 3: ((5>10) ? 5:10);
largest  = 3>10 ? 3 : 10
largest  = 10

Java

// Java Program to Find the Biggest of 3 Numbers

// Importing generic Classes/Files
import java.io.*;

class GFG {

    // Function to find the biggest of three numbers
    static int biggestOfThree(int x, int y, int z)
    {

        return z > (x > y ? x : y) ? z : ((x > y) ? x : y);
    }

    // Main driver function
    public static void main(String[] args)
    {

        // Declaring variables for 3 numbers
        int a, b, c;

        // Variable holding the largest number
        int largest;
        a = 5;
        b = 10;
        c = 3;
        // Calling the above function in main
        largest = biggestOfThree(a, b, c);

        // Printing the largest number
        System.out.println(largest
                           + " is the largest number.");
    }
}

Output

10 is the largest number.

Approach 2: Using the if-else statements

In this method, if-else statements will compare and check for the largest number by comparing numbers. ‘If’ will check whether ‘x’ is greater than ‘y’ and ‘z’ or not. ‘else if’ will check whether ‘y’ is greater than ‘x’ and ‘z’ or not. And if both the conditions are false then ‘z’ will be the largest number.

Java

// Java Program to Find the Biggest of 3 Numbers

// Importing generic Classes/Files
import java.io.*;

class GFG {

    // Function to find the biggest of three numbers
    static int biggestOfThree(int x, int y, int z)
    {

        // Comparing all 3 numbers
        if (x >= y && x >= z)

            // Returning 1st number if largest
            return x;

        // Comparing 2nd no with 1st and 3rd no
        else if (y >= x && y >= z)

            // Return z if the above conditions are false
            return y;

        else

            // Returning 3rd no, Its sure it is greatest
            return z;
    }

    // Main driver function
    public static void main(String[] args)
    {
        int a, b, c, largest;

        // Considering random integers three numbers
        a = 5;
        b = 10;
        c = 3;
        // Calling the function in main() body
        largest = biggestOfThree(a, b, c);

        // Printing the largest number
        System.out.println(largest
                           + " is the largest number.");
    }
}

Output

10 is the largest number.

Approach 3 : Using Collections.max() method and ArrayList

Java

// Java Program to Find the Largest of three Numbers
// Using Collections.max() method

import java.lang.*;
import java.util.*;

class GFG {

    public static void main(String[] args)
    {
        int a, b, c;
        // Considering random integers three numbers
        a = 5;
        b = 10;
        c = 3;
        ArrayList<Integer> x = new ArrayList<>();
        x.add(a);
        x.add(b);
        x.add(c);

        // Printing the largest number
        System.out.println(Collections.max(x)
                           + " is the largest number.");
    }
}

Output

10 is the largest number.

Time Complexity: O(n)
Auxiliary Space: O(n), where n is length of ArrayList.