C PROGRAMMING PROGRAM • OPERATORS & CONVERSIONS

Calculate the Average of Three Numbers

Learn how to calculate the average of three numbers using a clear C program.

BeginnerType castingAverageArithmetic

PROBLEM UNDERSTANDING

Input and expected output

Sample input

12 18 24

Sample output

Average = 18.00

COMPLETE C PROGRAM

Complete C implementation

#include <stdio.h>

int main(void)
{
    double first, second, third;

    printf("Enter three numbers: ");
    scanf("%lf %lf %lf", &first, &second, &third);
    printf("Average = %.2f\n", (first + second + third) / 3.0);
    return 0;
}

CURRENT STEP

Select Start to walk through the important lines.

SELECTED LINE

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EXPECTED OUTPUT FOR THE SAMPLE

Average = 18.00

0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

Read the required input values.
Add the three numbers and divide by 3.0 to retain a fractional result.
Display the computed result.

Add the three numbers and divide by 3.0 to retain a fractional result.

EFFICIENCY

Time and space complexity

Time complexity

O(1)

Auxiliary space

O(1)

DEBUGGING CHECKLIST

Common mistakes

Check this

Use the correct format specifier for every variable.

Check this

Initialize variables before using their values.

Check this

Check braces, semicolons and input order carefully.

Try it yourself

Practice: Run the program with the sample input, predict its output, and then test one boundary case of your own.