C PROGRAMMING PROGRAM • STRINGS

Reverse a String

Learn how to reverse a string using a clear C program.

BeginnerStringsTwo pointersIn-place swap

PROBLEM UNDERSTANDING

Input and expected output

Sample input

CodeBhavya

Sample output

Reversed: ayvahBedoC

COMPLETE C PROGRAM

Complete C implementation

#include <stdio.h>
#include <string.h>

int main(void)
{
    char text[200];

    fgets(text, sizeof text, stdin);
    text[strcspn(text, "\n")] = '\0';
    int left = 0, right = (int) strlen(text) - 1;
    while (left < right) {
        char temporary = text[left]; text[left] = text[right]; text[right] = temporary;
        left++; right--;
    }
    printf("Reversed: %s\n", text);
    return 0;
}

CURRENT STEP

Select Start to walk through the important lines.

SELECTED LINE

No line selected

EXPECTED OUTPUT FOR THE SAMPLE

Reversed: ayvahBedoC

0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

Read the required input values.
Swap characters at symmetric positions while moving two pointers inward.
Display the computed result.

Swap characters at symmetric positions while moving two pointers inward.

EFFICIENCY

Time and space complexity

Time complexity

O(n)

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.