⑯Find Largest of Three Numbers (with complete explanation and output examples)

 

✅ Find Largest of Three Numbers

🔹 Problem Statement

Given three numbers, find which one is the largest.

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🧠 Method 1: Using Simple if-else Conditions (Best Method)

🔸 Logic Explanation

Suppose the numbers are:

• a

• b

• c

Steps:

1. Compare a with both b and c.

2. If a is greater than or equal to both → a is largest.

3. Otherwise compare b with a and c.

4. If b is greater than or equal to both → b is largest.

5. Else → c is largest.

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💻 C Program

#include <stdio.h>

int main() {
    int a, b, c;

    printf("Enter three numbers: ");
    scanf("%d %d %d", &a, &b, &c);

    if (a >= b && a >= c) {
        printf("Largest number is: %d", a);
    }
    else if (b >= a && b >= c) {
        printf("Largest number is: %d", b);
    }
    else {
        printf("Largest number is: %d", c);
    }

    return 0;
}

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🔍 Dry Run Example 1

Input:

a = 10
b = 25
c = 15

Execution:

• Check: 10 >= 25 && 10 >= 15 ❌ False

• Check: 25 >= 10 && 25 >= 15 ✅ True

Output:

Largest number is: 25

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🧠 Method 2: Using Nested if

if(a > b) {
    if(a > c)
        printf("Largest is %d", a);
    else
        printf("Largest is %d", c);
}
else {
    if(b > c)
        printf("Largest is %d", b);
    else
        printf("Largest is %d", c);
}

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🧠 Method 3: Using Ternary Operator (Short Method)

int largest = (a > b) ? 
              ((a > c) ? a : c) : 
              ((b > c) ? b : c);

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⚡ Time Complexity

• Only comparisons

• Time Complexity = O(1) (constant time)

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🎯 Important Points for Exams

✔ Use >= to handle equal values
✔ Always check all conditions carefully
✔ Works for negative numbers also

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✅ Conclusion

This program efficiently calculates how to find largest of three numbers. It is beginner-friendly and commonly asked in C programming interviews and exams.

📘 C Programming Series – What’s Next?
👉 In the next post of this series, we will learn Patterns with complete explanation and output examples. Stay tuned! 🚀