Palindrome using C Programming

7/28/2019 Palindrome using C Programming

1/19

/*This program will recognise a string input by user is in the

language L,

where L = {w$w': w is a possibly empty string of characters

other than $, w' = reverse(w)}*/

#include /* Define standard input output routine */

/* Declaration of Stack data structure */

#define SIZE 10 /* Size of Stack */

typedef struct{

int items[SIZE];

int top;

}

STACK;

/* Declaration of function prototypes */

void push();

int pop();

void display();

int is_overflow();

int is_empty();

int main(){

STACK stck;

char str[100];

int a, flag;

stck.top = -1;


2/19

printf("This program will check whether the string is in

language\n");

printf("L = {w$w': w is a possibly empty string of

characters \n");

printf("other than $, w' = reverse(w)}\n");

printf("========================================================

=\n");

printf("Enter a string: "); /* Prompt user to input */

gets(str);

for(a=0;str[a]!='\0'; a++)

push(&stck, str[a]);

flag = 1;

for(a=0;str[a]!='$';a++){ /* Character $

will act as mirror between */

if(str[a] != pop(&stck)){ /* left and right

char of the string */

flag = 0;

break;

}

}

if(flag == 1){

printf("\nThe above string is in the

language\n");

}

else{


3/19

printf("\nThe above string is not in the

language\n");

}

getchar();

return 0;

}//main

//FUNCTIONS

void push(STACK *p, int element){ /* Function for PUSH

operation */

(p->top)++;

p->items[p->top] = element;

}

int pop(STACK *p){

return (p->items[(p->top)--]); /* Function for POP

operation */

}

/*Function to check stack overflow condition */

int is_overflow(int top){

if(top == SIZE - 1)

return(1);

else

return(0);

}


4/19

/* Function to check stack empty condition */

int is_empty(int top){

if(top == -1)

return(1);

else

return(0);

}


5/19

/* Write a C program to implement stack. Stack is a LIFO data

strcuture *

* LIFO - Last in First Out

*

* Perform PUSH(insert operation), POP(Delete operation) and

Display stack */

#include

#include

#define MAXSIZE 5

struct stack /* Structure definition for stack */

{

int stk[MAXSIZE];

int top;

};

typedef struct stack STACK;

STACK s;

/* Function declaration/Prototype*/

void push (void);

int pop(void);

void display (void);

int main ()


6/19

{

int choice;

int option = 1;

s.top = -1;

printf ("STACK OPERATION\n");

while (option)

{

printf ("-----------------------------------

-------\n");

printf (" 1 --> PUSH

\n");

printf (" 2 --> POP

\n");

printf (" 3 --> DISPLAY

\n");

printf (" 4 --> EXIT \n");

printf ("-----------------------------------

-------\n");

printf ("Enter your choice\n");

scanf ("%d", &choice);

switch (choice)

{

case 1: push();


7/19

break;

case 2: pop();

break;

case 3: display();

break;

case 4: return;

}

fflush (stdin);

printf ("Do you want to continue(Type 0 or

1)?\n");

scanf ("%d", &option);

}

getch();

return 0;

}

/*Function to add an element to the stack*/

void push ()

{

int num;

if (s.top == (MAXSIZE - 1))

{

printf ("Stack is Full\n");

return;

}


8/19

else

{

printf ("Enter the element to be pushed\n");

scanf ("%d", &num);

s.top = s.top + 1;

s.stk[s.top] = num;

}

return;

}

/*Function to delete an element from the stack*/

int pop ()

{

int num;

if (s.top == - 1)

{

printf ("Stack is Empty\n");

return (s.top);

}

else

{

num = s.stk[s.top];

printf ("poped element is = %d\n",

s.stk[s.top]);

s.top = s.top - 1;


9/19

}

return(num);

}

/*Function to display the status of the stack*/

void display ()

{

int i;

if (s.top == -1)

{

printf ("Stack is empty\n");

return;

}

else

{

printf ("\nThe status of the stack is\n");

for (i = s.top; i >= 0; i--)

{

printf ("%d\n", s.stk[i]);

}

}

printf ("\n");

}


10/19


11/19

4 --> EXIT------------------------------------------Enter your choice3The status of the stack is

784523Do you want to continue(Type 0 or 1)?1------------------------------------------

1 --> PUSH2 --> POP

3 --> DISPLAY4 --> EXIT

------------------------------------------Enter your choice2poped element is = 78Do you want to continue(Type 0 or 1)?1------------------------------------------

1 --> PUSH2 --> POP

3 --> DISPLAY

4 --> EXIT------------------------------------------Enter your choice3The status of the stack is4523Do you want to continue(Type 0 or 1)?0


12/19

#include

#include

#include

#define SIZE 10

typedef struct

{

int items[SIZE];

int top;

}STACK;

void push();

int pop();

void display();

int isoverflow();

int isempty();

int main()

{

STACK s;

char str[100];

int i, flag;


13/19

s.top = -1;

printf("\nEnter a string: ");

gets(str);

for(i=0;str[i]!='\0'; i++)

push(&s, str[i]);

flag = 1;

for(i=0;str[i]!='\0';i++)

{

if(str[i] != pop(&s))

{

flag = 0;

break;

}

}

if(flag == 1)

printf("\nEntered string is palindrome\n");

else

printf("\nEntered string is not a

palindrome\n");

getch();

return 0;


14/19

}

void push(STACK *p, int element)

{

if(isoverflow(p->top))

{

printf("\nStack is overflow");

}

else

{

(p->top)++;

p->items[p->top] = element;

}

}

int pop(STACK *p)

{

if(isempty(p->top))

{

printf("\nStack is underflow");

}

else

{

return (p->items[(p->top)--]);

}


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}

void display(STACK s)

{

int i;

if(isempty(s.top))

{

printf("\nStack is empty");

}

else

{

for(i=s.top; i>=0; i--)

{

printf("\n%d", s.items[i]);

}

}

}

//Function to check stack overflow condition

int isoverflow(int top)

{

if(top == SIZE - 1)

return (1);

else

return (0);


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}

//Function to check stack empty condition

int isempty(int top)

{

if(top == -1)

return (1);

else

return (0);

}


17/19

// This program determine if a word is a palindrome or not using

stack and pointer.

#include

#include

#include

#include

#define SIZE 50

//function declarations

void push(char i);

char pop(void);

//pointers declarations and stack declaration

char stack[SIZE];

char *top = stack;

char *bottom = stack;

int main(){

//declare a char array of size

char string[SIZE];

printf("Enter string: ");

scanf("%s", &string);


18/19

//printf("Your string is: %s \n", &string );

int i;

//push characters onto stack

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

{

if(isalnum(string[i]) && !isspace(string[i])) //if a

character in the string s is a digit or alphabet character and

not a white space

{

char c = tolower(string[i]);

push(c);//push onto stack

}

}

/* visualize the stack

printf("Your stack currently has: ");

for(i=0; i < strlen(string); i++){

char temp=stack[i];

printf("%c", temp);

}

printf("\n");*/

// pop the stack

for(i=0; i < strlen(string); i++){

char currItem = pop();


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if(currItem != *bottom){

printf("NOT a palindrome.\n");

return 0;

}

else{

bottom++;

}

}

printf("This is a palindrome.\n");

getch();

return 0;

}

// push function

void push(char i){

*top = i;

top++;

}

// pop function

char pop(void){

top--;

return *top;

}

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Palindrome using C Programming