逆波兰计算器

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <math.h>

#define IncreSize 10
#define InitSize 10

typedef int status;
typedef int Elemtype;

typedef struct sStack
{
    Elemtype *base;
    Elemtype *top;
    int StackSize;
}sqStack;

void InitStack(sqStack *s)
{
    s->base = (Elemtype *)malloc(sizeof(int)*InitSize);
    if(!s->base)
        exit(0);
    else
    {
        s->top = s->base;
        s->StackSize = InitSize;
        //return OK;
    }
}

void Push(sqStack *s, Elemtype e)
{
    if(s->top - s->base >= s->StackSize)
    {
        s->base = (Elemtype *)realloc(s->base,(s->StackSize + IncreSize)*sizeof(Elemtype));  //这里申请的大一些的空间;
        if(!s->base)
            exit (0);
    }
    *(s->top) = e;
    s->top++;
    //return OK;
}

void Pop(sqStack *s, Elemtype *e)
{
    if(s->top == s->base)
        exit(0);
    *e = *--(s->top);
   // return OK;
}

int StackLen(sqStack s)
{
    return(s.top - s.base);   //注意这里的结果是栈中的数据个数;
}

//输入数字,然后根据计算法则进行求解。
int main()
{
    char c;
    char str[20];         //设立一个缓冲区;
    int i = 0;
    int d,e,f;
    sqStack s;
    InitStack(&s);
    scanf("%c", &c);
    while(c != '#')
    {
        while( isdigit(c) || c == '.')
        {
            str[i++] = c;
            str[i] = '';
            if(i >= 10)
            {
                printf("过界
");
                return -1;
            }
            scanf("%c", &c);
            if(c == ' ')
            {
                d = atof(str);
                Push(&s,d);
                i = 0;
                break;
            }
        }
        switch(c)
        {
            case '+' :
                Pop(&s, &e);
                Pop(&s, &f);
                Push(&s,e+f);
                break;
            case '-':
                Pop(&s, &e);
                Pop(&s, &f);
                Push(&s,f-e);
                break;
            case '*':
                Pop(&s, &e);
                Pop(&s, &f);
                Push(&s,e*f);
                break;
            case '/':
                Pop(&s, &e);
                Pop(&s, &f);
                if(f == 0)
                    exit(0);
                Push(&s,e/f);
                break;
        }
        scanf("%c",&c);
    }
    Pop(&s,&e);
    printf("%d",e);
    return 0;
}

这个程序还是有些地方刚刚开始细节没有考虑清楚。

原文地址:https://www.cnblogs.com/wit-lq/p/4253236.html