栈的应用---平衡符号

判断一行字符串输入"各种括号"是否是合法的-----------------------栈用数组实现

如：[()]是合法的(balance)

[(])是不合法的(imbalance)

#include <stdio.h>#include <stdlib.h>#include <string.h>typedef struct Mystack *Stack;struct Mystack {    int Capacity;       /* 栈的容量 */    int Top_of_stack;   /* 栈顶下标 */    char *Array;        /* 存放栈中元素的数组 */};/* 栈的创建 */Stack CreateStack(int Max){    Stack S;    S = malloc(sizeof(struct Mystack));    if (S == NULL)        printf("Create stack error!\n");    S->Array = malloc(sizeof(char) * Max);    if (S->Array == NULL)        printf("Create stack error!\n");    S->Capacity = Max;    S->Top_of_stack = 0;    return S;}/* 释放栈 */void DisposeStack(Stack S){    if (S != NULL)    {           free(S->Array);        free(S);    }   }/* 判断一个栈是否是空栈 */int IsEmpty(Stack S){    return !S->Top_of_stack;}/* 判断一个栈是否满栈 */int IsFull(Stack S){    if (S->Top_of_stack == S->Capacity - 1)        return 1;    else        return 0;}/* 数据入栈 */int Push(int x, Stack S){    if (IsFull(S))        printf("The Stack is full!\n");    else        S->Array[S->Top_of_stack++] = x;}/* 数据出栈 */int Pop(Stack S){    if (IsEmpty(S))        printf("The Stack is empty!\n");    else        S->Top_of_stack--;}/* 将栈顶返回 */char Top(Stack S){    if (!IsEmpty(S))        return S->Array[S->Top_of_stack-1];    printf("The Stack is empty!\n");    return 0;}int main(){    int i, len;    char str[100];    printf("Please input the symbol that you want to balance: \n");    scanf("%s", str);    len = strlen(str);    /* 根据序列的长度来创建栈 */    struct Mystack *my_stack = CreateStack(len+1);    for (i = 0; i < len; i++)    {        if (str[i] == '{' || str[i] == '[' || str[i] == '(' )            Push(str[i], my_stack);        if (str[i] == '}')        {            if (Top(my_stack) == '{')                Pop(my_stack);            else                break;        }        else if (str[i] == ']')        {            if (Top(my_stack) == '[')                Pop(my_stack);            else                break;        }        else if (str[i] == ')')        {            if (Top(my_stack) == '(')                Pop(my_stack);            else                break;        }    }    /* 如果最后占空则序列是合法的 */    if(IsEmpty(my_stack))        printf("The symbol that you input is balance!\n");    else        printf("The symbol that you input is imbalance!\n");    DisposeStack(my_stack);    return 0;}

测试：

shang@shang:~/C$ ./a.out Please input the symbol that you want to balance: {[]}The symbol that you input is balance!shang@shang:~/C$ ./a.out Please input the symbol that you want to balance: [(])The symbol that you input is imbalance!shang@shang:~/C$ ./a.out Please input the symbol that you want to balance: ([{}])The symbol that you input is balance!shang@shang:~/C$