In C, a Find Maximum of Three Numbers program determines the largest number among three numbers entered by the user. This can be achieved by using conditional statements (if-else or nested if) to compare the numbers and identify the maximum.

Steps for the Program:

1. Include Header Files: Include stdio.h for input/output functions.
2. Declare Variables: Use three variables to store the numbers entered by the user.
3. Take Input: Ask the user to enter three numbers.
4. Compare the Numbers: Use conditional statements to compare the three numbers and determine the largest.
5. Display the Result: Print the largest number.

Program:

#include <stdio.h>

int main() {
    int num1, num2, num3;  // Declare variables to store three numbers

    // Ask the user to input three numbers
    printf("Enter three numbers: ");
    scanf("%d %d %d", &num1, &num2, &num3);

    // Compare the numbers and find the maximum
    if (num1 >= num2 && num1 >= num3) {
        // If num1 is greater than or equal to both num2 and num3, it is the largest
        printf("The largest number is: %d\n", num1);
    }
    else if (num2 >= num1 && num2 >= num3) {
        // If num2 is greater than or equal to both num1 and num3, it is the largest
        printf("The largest number is: %d\n", num2);
    }
    else {
        // Otherwise, num3 is the largest
        printf("The largest number is: %d\n", num3);
    }

    return 0;
}

Explanation:

1. Variables:

   • int num1, num2, num3: These three variables store the three numbers input by the user.

2. Input:

   • printf("Enter three numbers: ");: This statement prompts the user to enter three numbers.
   • scanf("%d %d %d", &num1, &num2, &num3);: This reads the three numbers entered by the user and stores them in num1, num2, and num3.

3. Comparing the Numbers:

   • The condition if (num1 >= num2 && num1 >= num3) checks if num1 is greater than or equal to both num2 and num3. If true, num1 is the largest number.
   • The else if (num2 >= num1 && num2 >= num3) checks if num2 is greater than or equal to both num1 and num3. If true, num2 is the largest number.
   • If neither of the above conditions is true, the program concludes that num3 is the largest number and prints it.

4. Output:

   • Based on the comparison, the largest number is printed using the printf function.

Sample Output:

Example 1:

Enter three numbers: 5 9 2
The largest number is: 9

Example 2:

Enter three numbers: 12 12 10
The largest number is: 12

Example 3:

Enter three numbers: 8 3 15
The largest number is: 15

Key Points:

• %d is the format specifier used to read and print integers.
• Conditional Logic: The program uses if-else if-else statements to compare the three numbers and determine the largest one.
• Handling Equal Numbers: The program correctly handles cases where two or more numbers are equal, and still outputs the maximum number.

This program is a simple example of using conditional logic in C to find the largest of three numbers based on user input.