关于符号是否匹配
#include "stdio.h"#include "conio.h"
#include "stdlib.h"
#define OK 1
#define ERROR -1
#define OVERFLOW -1
#define ENDFLAG 0
typedef int Status;
typedef int SElemType;
#define STACK_INIT_SIZE 100
#define STACLINCREMENT 10
typedef struct{
SElemType *base; /*栈的基地址*/
SElemType *top; /*栈顶指针*/
int stacksize;
}SqStack;//顺序栈
Status InitStack(SqStack *S)//构造一个空的栈
{
S->base=(SElemType *)malloc(STACK_INIT_SIZE*sizeof(SElemType));//malloc申请动态内存的专用函数
if(!S->base)
{
printf("/nOut of space./n");
getch();
exit(OVERFLOW);/*溢出*/
}
S->top=S->base;
S->stacksize=STACK_INIT_SIZE;
return OK;
}
Status push (SqStack *S,SElemType e)
{
if(S->top-S->base>=S->stacksize)
{
S->base=(SElemType *)realloc(S->base,(S->stacksize+STACLINCREMENT)*sizeof(SElemType));
//realloc 可以对给定的指针所指的空间进行扩大或者缩小,原有内存的中内容将保持不变
if(!S->base)
{ printf("\nOut of space.\n");
getch();
exit(OVERFLOW);
}
S->top=S->base+S->stacksize;
S->stacksize+=STACLINCREMENT;
}
*S->top++=e;
return OK;
}
Status pop(SqStack *S,SElemType *e)
{
if(S->top==S->base)
{
printf("\nThe stack is empty.\n");
return ERROR;
}
*e=*--S->top;
return OK;
}
void match(char str[])
{
SqStack S;
char *p;
SElemType e;
InitStack(&S);
p=str;
while (*p)
{
if (*p=='('||*p=='['||*p=='{')push(&S,*p);
else if(*p==')'||*p==']'||*p=='}')
{
if (*(S.top-1)+1==*p||*(S.top-1)+2==*p )
pop(&S,&e);
else{
printf("\nMismatch.\n");
return;
}
}
p++;
}
if(S.top==S.base)
printf("\nMatch.\n");
else
printf("\nMisamatch.\n");
}
void main (void)
{
char str[100];
printf("\nInput the expression:\n");
gets(str);
match(str);
getch();
}
//if (*(S.top-1)+1==*p||*(S.top-1)+2==*p )这句代码是什么意思?求解