1 #include<stdio.h> 2 #include<stdlib.h> 3 #include<string.h> 4 5 #define MAX 20 6 7 8 typedef struct stack{ 9 char item; 10 struct stack *next; 11 }stack; 12 13 char gettop_s(stack *h) //得到栈顶元素 14 { 15 char ch; 16 17 ch = h->item; 18 19 return ch; 20 } 21 22 stack * out_s(stack *h) //出栈 23 { 24 stack *p; 25 char ch; 26 27 28 p = h; 29 ch = p->item; 30 h = h->next; 31 32 free(p); 33 34 return h; 35 } 36 37 stack * insert_s(char ch, stack *h) //入栈 38 { 39 stack *p; 40 41 p = (stack *)malloc(sizeof(stack)); 42 43 p->item = ch; 44 p->next = h; 45 46 h = p; 47 48 return h; 49 } 50 51 stack * init() //初始化栈 52 { 53 stack *h; 54 55 h = (stack *)malloc(sizeof(stack)); 56 57 h->item = ' '; 58 h->next = NULL; 59 60 return h; 61 } 62 63 int cop_symbol(char a,char b) //判断两个符号是否匹配 64 { 65 if(a == '[' && b == ']') 66 return 1; 67 else if(a == '(' && b == ')') 68 return 1; 69 else 70 return 0; 71 } 72 73 int bracktext(char value[MAX], stack *h) //括号检测 74 { 75 int i = 0; 76 char topvalue; //栈顶元素 77 78 while(value[i] != ' '){ 79 80 if(h->next == NULL) 81 h = insert_s(value[i], h); 82 else{ 83 topvalue = gettop_s(h); 84 if(cop_symbol(topvalue, value[i])) 85 h = out_s(h); 86 else 87 h = insert_s(value[i], h); 88 } 89 i++; 90 } 91 92 if(h->next != NULL) 93 return 0; 94 else 95 return 1; 96 97 } 98 99 100 int main() 101 { 102 stack *h; 103 int i = 0; 104 char textvalue[MAX]; //存放需要测试的值 105 //栈头结点 106 puts("please enter some symbols you want to text"); 107 108 scanf("%s",textvalue); 109 110 h = init(); 111 112 if(bracktext(textvalue, h)) 113 printf("OK "); 114 else 115 printf("NO "); 116 117 }
进栈和出栈的时候要注意返回头指针，不然下次操作会找不到头结点。