逆波兰计算器：

逆波兰计算器：

#include 
#include 
#include 

#define Stack_Init_Size 20
#define Stack_Increasement 10
#define Max_Buffer_Size 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+Stack_Increasement)*sizeof(Elemtype));
        if(!s->base)
            exit(0);
    }
    *(s->top)=e;
    s->top++;
}
void pop(sqStack *s,Elemtype *e){
    if(s->top==s->base)
       exit(0);
    s->top--;
    *e=*(s->top);
}
int stackLen(sqStack s){
    return (s.top - s.base);
}

int isEmpty(sqStack s){
    return (s.top==s.base);
}

int main(){
    sqStack s;
    initStack(&s);
    char c;
    double d,e;
    char buffer[Max_Buffer_Size];
    int i=0;
    printf("请输入所要计算表达式的逆波兰表达式，数字(包括小数)之间用空格分开，以#表示结束！\n");
    scanf("%c",&c);
    while(c!='#'){
        while(isdigit(c)||c=='.'){
            buffer[i++]=c;
            buffer[i]='\0';
            if(i>=10){
                printf("\n出错！超过最大缓冲区大小！\n");
                return -1;
            }
            scanf("%c",&c);
            if(c==' '){
                d=atof(buffer);
                push(&s,d);
                i=0;
                break;
            }
        }

        switch(c){
            case '+':
            pop(&s,&d);
            pop(&s,&e);
            push(&s,d+e);
            break;
            case '-':
            pop(&s,&d);
            pop(&s,&e);
            push(&s,e-d);
            break;
            case '*':
            pop(&s,&d);
            pop(&s,&e);
            push(&s,d*e);
            break;
            case '/':
            pop(&s,&d);
            pop(&s,&e);
            if(e!=0){
                push(&s,e/d);
            }
            else{
                printf("\n出错，分母不能为0！");
                return -1;
            }
            break;
        }
        scanf("%c",&c);
    }
    pop(&s,&d);
    printf("\n最终结果为：%f\n",d);
    return 0;
}