SDUT 2133 数据结构实验之栈三：后缀式求值

后缀式求值的方法参见我的另一篇文章把运算符变成表达式

 1 #include<stdio.h>
 2 #include<string.h>
 3 int main()
 4 {
 5     int top = 0,i,k,s,num[50];
 6     char str;
 7     while(scanf("%c", &str),str!='#')
 8     {
 9         if(str>='0'&&str<='9')
10             num[++top] = str-48;
11         else
12         {
13             switch(str)
14             {
15             case '+':s = (num[top-1])+(num[top]);break;
16             case '-':s = (num[top-1])-(num[top]);break;
17             case '*':s = (num[top-1])*(num[top]);break;
18             case '/':s = (num[top-1])/(num[top]);break;
19             }
20             top--;
21             num[top] = s;
22         }
23     }
24     printf("%d\n",num[top]);
25     return 0 ;
26 }