C program to Reverse a String using STACK

0 Mfleg.vhm October 04, 2021

Reversing string is an operation of Stack by using Stack we can reverse any string, here we implemented a program in C - this will reverse given string using Stack.

/*C program to Reverse String using STACK*/

#include <stdio.h>

#include <string.h>

#define MAX 100   /*maximum no. of characters*/

/*stack variables*/

int top=-1;

int item;

/***************/

/*string declaration*/

char stack_string[MAX];

/*function to push character (item)*/

void pushChar(char item);

/*function to pop character (item)*/

char popChar(void);

/*function to check stack is empty or not*/

int isEmpty(void);

/*function to check stack is full or not*/

int isFull(void);

int main()

{

    char str[MAX];

    int i;

    printf("Input a string: ");

    scanf("%[^\n]s",str); /*read string with spaces*/

    /*gets(str);-can be used to read string with spaces*/

    for(i=0;i<strlen(str);i++)

        pushChar(str[i]);

    for(i=0;i<strlen(str);i++)

        str[i]=popChar();

    printf("Reversed String is: %s\n",str);

    return 0;

}

/*function definition of pushChar*/

void pushChar(char item)

{

    /*check for full*/

    if(isFull())

    {

        printf("\nStack is FULL !!!\n");

        return;

    }

    /*increase top and push item in stack*/

    top=top+1;

    stack_string[top]=item;

}

/*function definition of popChar*/

char popChar()

{

    /*check for empty*/

    if(isEmpty())

    {

        printf("\nStack is EMPTY!!!\n");

        return 0;

    }

    /*pop item and decrease top*/

    item = stack_string[top];

    top=top-1;

    return item;

}

/*function definition of isEmpty*/

int isEmpty()

{

    if(top==-1)

        return 1;

    else

        return 0;

}

/*function definition of isFull*/

int isFull()

{

    if(top==MAX-1)

        return 1;

    else

        return 0;

}