用栈表现逆波兰算法，第九行我用char，答案就不对，double.就对了.
#include <stdio.h>#include <stdlib.h>
#include <ctype.h>
#define STACK_INIT_SIZE 20
#define STACKINFREMENT10
#define MAXBUFFER 10
typedef double ElemType;
typedef struct
{
ElemType *base;
ElemType *top;
int stackSize;
}sqStack;
void InitStack(sqStack *s)
{
s->base = (ElemType *)malloc(STACK_INIT_SIZE * sizeof(ElemType));
if(!s->base)
{
exit(0);
}
s->top = s->base;
s->stackSize = STACK_INIT_SIZE;
}
void Push(sqStack *s,ElemType e)
{
if(s->top - s->base >= s->stackSize)
{
s->base = (ElemType *)realloc(s->base,(s->stackSize +STACKINFREMENT)*sizeof(ElemType));
if(!s->base)
{
exit(0);
}
}
*(s->top) = e;
s->top++;
}
void Pop(sqStack *s ,ElemType *e)
{
if(s->top == s->base)
{
return;
}
*e= *-- (s->top);
}
int StackLen(sqStack s)
{
return(s.top - s.base);
}
int main()
{
sqStack s;
char c;
double d,e;
char str;
int i = 0;
InitStack( &s );
printf("请按逆波兰表达式输入待计算数据，数据与运算符之间用空格隔开,以#作为结束标志。\n");
scanf("%c",&c);
while( c!='#' )
{
while( isdigit(c)|| c=='.') //用于过滤数字。
{
str = c;
str ='\0';
if(i >= 10)
{
printf("出错!单个数据过大。\n");
return -1;
}
scanf("%c",&c);
if( c==' ' )
{
d = atof(str);
Push(&s ,d);
i = 0;
break;
}
}
switch(c)
{
case '+':
Pop(&s,&e);
Pop(&s,&d);
Push(&s,d+e);
break;
case '-':
Pop(&s ,&e);
Pop(&s ,&d);
Push(&s, d-e );
break;
case '*':
Pop(&s ,&e);
Pop(&s ,&d);
Push(&s, d*e);
break;
case '/':
Pop(&s ,&e);
Pop(&s ,&d);
if(e!=0)
{
Push(&s ,d/e);
}
else
{
printf("\n出错，除数为零！");
return -1;
}
break;
}
scanf("%c",&c);
}
Pop(&s ,&d);
printf("\n最终的计算结果为：%f\n",d);
return 0;
}
希望哪位大佬帮忙解释下，刚刚接触数据结构算法，不太理解。
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