Example: String Reversal using Stack in C

// String Reversal using Stack
#include <stdio.h>
#include <string.h>
#include <stdlib.h> // For malloc and free

// Simple Stack implementation for characters
#define MAX_SIZE 100 // Maximum size of the stack

char stack[MAX_SIZE];
int top = -1; // Initialize top of stack

void push(char c) {
    if (top == MAX_SIZE - 1) {
        printf("Stack Overflow!\n");
        return;
    }
    stack[++top] = c;
}

char pop() {
    if (top == -1) {
        printf("Stack Underflow!\n");
        return '\0'; // Return null character for error
    }
    return stack[top--];
}

void reverseStringStack(char *str) {
    int i;
    // Step 1: Push all characters of the string onto the stack
    for (i = 0; i < strlen(str); i++) {
        push(str[i]);
    }

    // Step 2: Pop all characters from the stack back into the string
    for (i = 0; i < strlen(str); i++) {
        str[i] = pop();
    }
}

int main() {
    char myString[] = "data structures";
    printf("Original string: %s\n", myString);

    reverseStringStack(myString);
    printf("Reversed string: %s\n", myString);

    return 0;
}