这个程序自己写的有些局限,可惜只能对0~9的四则运算起作用,我正在对它进行改进,希望各位能提出好的意见,谢谢!!
#include<stdio.h>
#include<math.h>
#include<stdlib.h>
#include<ctype.h>
#define maxism 15
typedef strUCt stack
{
char stack[maxism];
int top;
}stack;
stack *L;
char after[maxism];
void initialstack(stack *T)
void push(stack *T,int x)
void change()
{
int i=0,j,m=0;
char str[maxism],ch;
printf("please enter the compute eXPression(only contained +,-,*,/,(,),begin and end with '#'): ");
gets(str);
i++;
ch=str[i];
initialstack(L);
while(ch!='#')
{
switch(ch)
{
case'(':
L->top++;
L->stack[L->top]=ch;
break;
case')':
while(L->stack[L->top]!='(')
{
after[m]=L->stack[L->top];
L->top--;
m++;
}
L->top--;
break;
case'+':
case'-':
while(L->top!=0&&L->stack[L->top]!='(')
{
after[m]=L->stack[L->top];
L->top--;
m++;
}
L->top++;
L->stack[L->top]=ch;
break;
case'*':
case'/':
while(L->stack[L->top]=='*'L->stack[L->top]=='/')
{
after[m]=L->stack[L->top];
L->top--;
m++;
}
L->top++;
L->stack[L->top]=ch;
break;
case' ':
break;
default:
if(ch>='0'&&ch<='9')
{
after[m]=ch;
m++;
}
else
{
printf("error! ");
exit(1);
}
}
i++;
ch=str[i];
}
while(L->stack[L->top]!=0)
printf("the changed expression is: ");
for(j=0;j<m;j++)
printf("%c",after[j]);
after[m]='#';
printf("%c",after[m]);
}
void compute(stack *L)
{
int i=0,result,d;
char ch;
initialstack(L);
ch=after[i];
while(ch!='#')
{
while(ch>='0'&&ch<='9')
{
d=ch-'0';
push(L,d);
i++;
ch=after[i];
}
switch(ch)
{
case'+':
L->stack[L->top-1]=L->stack[L->top]+L->stack[L->top-1];
L->top--;
break;
case'-':
L->stack[L->top-1]=L->stack[L->top-1]-L->stack[L->top];
L->top--;
break;
case'*':
L->stack[L->top-1]=L->stack[L->top]*L->stack[L->top-1];
L->top--;
break;
case'/':
if(L->stack[L->top-1]==0)
{
printf("error due to the wrong input format! ");
exit(0);
}
else
L->stack[L->top-1]=L->stack[L->top-1]/L->stack[L->top];
L->top--;
break;
default:
break;
}
i++;
ch=after[i];
}
printf(" the final result is:%d",L->stack[L->top]);
}
main()
{int result;
clrscr();
change();
compute(L);
}
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