用棧實現了判斷迴文數的操作，即把字串依次入棧，然後出棧並依次和字元陣列比較是否相等，從而判斷字元序列是否迴文數，程式碼如下：

#include "stdio.h"

#include "stdlib.h"

#include "string.h"

#define EMPTY 0

#define FULL 10000

#define MAX 10000

typedef char data;

typedef struct elem {

data d;

struct elem *next;

}elem;

typedef struct stack {

int cnt;

elem *top;

}stack;

void initialize(stack *stk);

void push(data d, stack *stk);

data pop(stack *stk);

bool empty(const stack *stk);

bool full(const stack *stk); //棧操作函式

void initialize(stack *stk)

{

stk->cnt = 0;

stk->top = NULL;

}

bool empty(const stack *stk)

{

return stk->cnt == EMPTY;

}

bool full(const stack *stk)

{

return stk->cnt == FULL;

}

void push(data d, stack *stk)

{

elem *p;

if (!full(stk))

{

p = (elem *)malloc(sizeof(elem));

p->d = d;

p->next = stk->top;

stk->top = p;

stk->cnt++;

}

}

data pop(stack *stk)

{

data d;

elem *p;

if(!empty(stk))

{

d = stk->top->d;

p = stk->top;

stk->top = stk->top->next;

stk->cnt--;

free(p);

}

return d;

}

int main(void)

{

data input[MAX];

stack temp;

int i = 0;

int flag = 0;

initialize(&temp); //初始化臨時棧

scanf("%s", &input); //輸入字串

while (input[i] != "@")

{//字串入棧

push(input[i], &temp);

i++;

}

while (!empty(&temp))

{//字元依次出棧和字元陣列比較，判斷是否迴文數

if (temp.top->d == input[flag])

{

pop(&temp);

flag++;

}

else

{

printf("此字元序列不是迴文數!\n");

break;

}

}

if (empty(&temp))

printf("此字元序列是迴文數!\n");

return 1;

}

執行結果：