[shania]

hello guys!

my goal is to test if the string inputted by the user is palindrome or not using stack and queue..but now i am having a trouble in my queue program...can you please check my code and tell me what is the problem...thank you..

here's my code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX 100

typedef struct stack {
        char value;
        struct stacknode *next;
}STACK_NODE;

typedef struct ListNode {
        char element;
        struct ListNode *next;
}ListNode;

typedef struct Q {
        ListNode *frontOfQueue;
        ListNode *rearOfQueue;
        int numElements;
} Queue;


void initStack(STACK_NODE** head);
void push(STACK_NODE** head, char input);
void stackfunction(char* input);
int isEmptyStack(STACK_NODE** head);

void initQueue(Queue *q);
void enqueue(Queue *q, char input);
int IsEmptyQ(Queue* q);
void queuefunction(char *input);

main()
{
    char* string = (char*)malloc(MAX+1* sizeof(char));
    char* stringq = (char*)malloc(MAX+1* sizeof(char));

    char option;
    do
    {
        printf("\n\tInput string: ");
        fflush(stdin);
        gets(string);
        stackfunction(string);
        queuefunction(stringq);
        printf("\n\tstack:  %s",string);
        printf("\n\tqueue:  %s",stringq);

        printf("\n\n\tDo you want to continue? [Y/N]: ");
        option=getchar();
    }while(toupper(option)=='y');
    printf("\n\n\tProgram Terminated...\n");
	return 0;
}

void initStack(STACK_NODE** head){
    *head = NULL;
}

void push(STACK_NODE** head, char input){
    STACK_NODE* temp = (STACK_NODE*)malloc(sizeof(STACK_NODE));
    temp->value =input;
    temp->next = *head;
    *head = temp;
}
int isEmpty(STACK_NODE** head){

    if(*head==NULL){
        printf("Stack is empty!");
        return 1;
    }
}

void stackfunction(char* input){

    STACK_NODE* head = (STACK_NODE*)malloc(sizeof(STACK_NODE));
    initStack(&head);

    while(*input != '\0') {
        push(&head,*input);
              input++;
   }
}

void queuefunction(char *input){

    Queue* head = (Queue*)malloc(sizeof(Queue));
    initQueue(&head);

    while(*input != '\0') {
        enqueue(&head,*input);
              input++;
   }
}

void initQueue(Queue *q){
     q->frontOfQueue = NULL;
     q->rearOfQueue = NULL;
     q->numElements=0;
}

void enqueue(Queue *q, char input) {
     ListNode *temp= (ListNode*)malloc(sizeof(ListNode));

     //out of memory
     if (temp == NULL){
              printf("error");
              return;
     }

     //add element to listnode
     temp->element =input;
     temp->next=NULL;

     if(IsEmptyQ(&(*q))){
              q->frontOfQueue = temp;
              q->rearOfQueue = temp;
     }
     else {
              q->rearOfQueue->next = temp;
              q->rearOfQueue = temp;
     }
     q->numElements++;
}

int IsEmptyQ(Queue* q)
{
  return(q->frontOfQueue==NULL);
}