Find Greatest of Two or Three Numbers | C, C++, Java

Algorithm

1. Input two numbers from the user.
2. Compare both numbers using if-else.
3. Print the greatest number accordingly.

Implementation in C

#include <stdio.h>

int main() {
    int num1, num2;

    // Input two numbers
    printf("Enter two numbers: ");
    scanf("%d %d", &num1, &num2);

    // Find the greatest number
    if (num1 > num2) {
        printf("The greatest number is: %d\n", num1);
    } else if (num2 > num1) {
        printf("The greatest number is: %d\n", num2);
    } else {
        printf("Both numbers are equal.\n");
    }

    return 0;
}

Explanation

• Takes two integer inputs.
• Uses an if-else statement to compare the numbers.
• Prints the greater number, or states if both numbers are equal.

Finding the Greatest of Three Numbers

Algorithm

1. Input three numbers from the user.
2. Use if-else statements to compare the numbers.
3. Determine the greatest number and print the result.

Implementation in C

#include <stdio.h>

int main() {
    int num1, num2, num3;

    // Input three numbers
    printf("Enter three numbers: ");
    scanf("%d %d %d", &num1, &num2, &num3);

    // Find the greatest number using if-else
    if (num1 >= num2 && num1 >= num3) {
        printf("The greatest number is: %d\n", num1);
    } else if (num2 >= num1 && num2 >= num3) {
        printf("The greatest number is: %d\n", num2);
    } else {
        printf("The greatest number is: %d\n", num3);
    }

    return 0;
}

Explanation

• Takes three integer inputs.
• Uses logical AND (&&) to check which number is the largest.
• Prints the greatest number among the three.

Alternative Approach Using Ternary Operator

Instead of using if-else, the ternary operator (? :) can be used for concise code.

C Program to Find Greatest of Two Numbers Using Ternary Operator

#include <stdio.h>

int main() {
    int num1, num2;

    // Input two numbers
    printf("Enter two numbers: ");
    scanf("%d %d", &num1, &num2);

    // Find the greatest number using ternary operator
    int greatest = (num1 > num2) ? num1 : num2;

    printf("The greatest number is: %d\n", greatest);

    return 0;
}

C Program to Find Greatest of Three Numbers Using Ternary Operator

#include <stdio.h>

int main() {
    int num1, num2, num3;

    // Input three numbers
    printf("Enter three numbers: ");
    scanf("%d %d %d", &num1, &num2, &num3);

    // Find the greatest number using nested ternary operator
    int greatest = (num1 > num2) ? ((num1 > num3) ? num1 : num3) 
                                 : ((num2 > num3) ? num2 : num3);

    printf("The greatest number is: %d\n", greatest);

    return 0;
}

Explanation of Ternary Operator Approach

• Uses nested ternary operators for comparison.
• Makes the program more compact and efficient.

Test Cases

Complexity Analysis

Both approaches run in constant time O(1) since only a few comparisons are made.

Conclusion

• The if-else method is easy to understand and implement.
• The ternary operator method is concise and efficient.
• Both methods provide optimal performance for determining the largest number.

These programs are frequently asked in placement interviews and are useful for building logic in competitive programming.