C PROGRAMMING PROGRAM • OPERATORS & CONVERSIONS

Reverse a Three-Digit Number

Learn how to reverse a three-digit number using a clear C program.

BeginnerDigit extractionPlace valueArithmetic

PROBLEM UNDERSTANDING

Input and expected output

Sample input

Sample output

Reversed number = 275

COMPLETE C PROGRAM

Complete C implementation

#include <stdio.h>

int main(void)
{
    int number, reversed;

    printf("Enter a three-digit positive integer: ");
    scanf("%d", &number);
    reversed = (number % 10) * 100 + ((number / 10) % 10) * 10 + number / 100;
    printf("Reversed number = %d\n", reversed);
    return 0;
}

CURRENT STEP

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SELECTED LINE

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EXPECTED OUTPUT FOR THE SAMPLE

Reversed number = 275

0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

Read the required input values.
Extract each digit and rebuild the number with reversed place values.
Display the computed result.

Extract each digit and rebuild the number with reversed place values.

EFFICIENCY

Time and space complexity

Time complexity

O(1)

Auxiliary space

O(1)

DEBUGGING CHECKLIST

Common mistakes

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Use the correct format specifier for every variable.

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Initialize variables before using their values.

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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.