7.4 括号匹配

7-5 parenthesis.c

 1 #include <stdio.h>
 2 #define MAXLENGTH 80   //最大字符串长度
 3 #define STACK_INIT_SIZE  100
 4 #define SIZE_INCREMENT  5
 5 typedef struct //栈结构
 6 {
 7     int *base; //栈底
 8     int *top; //栈顶
 9     int stacksize; //栈大小
10 }SqStack,*SQSTACK;
11 int StackInit(SQSTACK s) //初始化栈
12 {
13     s->base=(int *)malloc(STACK_INIT_SIZE*sizeof(int));
14     if(!(s->base))
15         exit(0);
16     s->top=s->base;
17     s->stacksize=STACK_INIT_SIZE;
18     return 1;
19 }
20 int PUSH(SQSTACK s,int e) //入栈
21 {
22     if(s->base+s->stacksize==s->top)
23     {
24         s->base=(int *)realloc(s->base,(SIZE_INCREMENT+s->stacksize)*sizeof(int));
25         s->top=s->base+s->stacksize;
26         s->stacksize+=SIZE_INCREMENT;
27     }
28     *(s->top)=e;
29      s->top+=1;
30      return 1;
31 }
32 int POP(SQSTACK s,int *p) //出栈
33 {
34     if(s->base==s->top) //空栈
35         return 0;
36      *p=*(s->top-1);
37      s->top--;
38      return 1;
39 }
40 int StackLength(SQSTACK s) //栈的长度(元素数量)
41 {
42     return (s->top-s->base);
43 }
44 int StackFree(SQSTACK s) //释放栈
45 {
46     free(s->base);
47     s->top=s->base=NULL;
48     return 1;
49 }
50
51 void ParenthesisMatch(char *expr)
52 {
53     SqStack s;
54     int i,len,no;
55     if(!StackInit(&s)) //初始化栈失败
56         exit(0);//退出
57     len=strlen(expr); //取字符串长度
58     for(i=1;i<=len;i++)
59     {
60         if(expr[i-1]==‘(‘)
61             PUSH(&s,i); //左插号位置序号入栈
62         else if(expr[i-1]==‘)‘)
63         {
64             if(POP(&s,&no))
65                 printf("括号配对:%d -- %d\n", no,i);
66             else
67                 printf("没有左括号与位于第%d个位置的右侧号配对!\n",i);
68         }
69     }
70     while(StackLength(&s)>0) //若栈中还有数据，表示还有左括号没配对
71     {
72         POP(&s,&no);
73         printf("位于第%d位置的左括号没有配对的右括号!\n", no);
74     }
75     StackFree(&s);                                        //释放栈
76 }
77 int main()
78 {
79     char expr[MAXLENGTH];
80     printf("输入一个带括号的表达式(长度不超过%d个字符):\n",MAXLENGTH);
81     scanf("%s",expr);
82     ParenthesisMatch(expr);
83
84     getch();
85     return 0;
86 }