DATA STRUCTURES PROGRAM • STACKS & EXPRESSIONS

Reverse a String Using a Stack

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

BeginnerStackLIFOpush/pop

PROBLEM UNDERSTANDING

Input and expected output

Sample input

No input required

Sample output

Reversed = KCATS

COMPLETE C PROGRAM

Complete C implementation

#include <stdio.h>
#include <stddef.h>

int main(void)
{
    char text[] = "STACK";
    char stack[20];
    int top = -1;
    for (size_t index = 0; text[index] != '\0'; index++) stack[++top] = text[index];
    for (size_t index = 0; text[index] != '\0'; index++) text[index] = stack[top--];
    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 = KCATS

0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

Read the required input values.
Push characters in normal order and pop them in reverse order.
Display the computed result.

Push characters in normal order and pop them in reverse order.

EFFICIENCY

Time and space complexity

Time complexity

O(n)

Auxiliary space

O(n)

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.