程序代码：

#include<stdio.h>
#ifndef STACK_H_INCLUDED
#define STACK_H_INCLUDED
typedef struct Node
{
    char Date;
    struct Node *Next;
} LinkStack;//定义结构体
LinkStack *CreateStack()//创建栈
{
    LinkStack *S;
    S = (LinkStack*)malloc(sizeof(struct Node));//分配空间
    S->Next = NULL;//初始化，即栈为空栈
    return S;
}
int IsEmpty(LinkStack *S)//IsEmpty的意思是说明这个链栈已经初始化
{
    return(S->Next == NULL);
}
void Push(LinkStack *S, char item)
{
    LinkStack *TmpCell;
    TmpCell = (LinkStack*)malloc(sizeof(struct Node));
    TmpCell->Date = item;/*为栈分配数据域和指针域，数据域就是前面定义过的字符item，指针域TmpCell是什么?TmpCell是人员自定的一个变量名*/
    TmpCell->Next = S->Next;
    S->Next = TmpCell;//插入TmpCell
}
char Pop(LinkStack *S)//Pop即出栈操作
{
    LinkStack *FirstCell;
    char TopElem;//栈顶元素
    if(IsEmpty(S))
    {
        return NULL;
    }
    else
    {
        FirstCell = S->Next;
        S->Next = FirstCell->Next;
        TopElem = FirstCell->Date;
        free(FirstCell);
        return TopElem;
    }
}

#endif // STACK_H_INCLUDED
#include <stdio.h>
#include <stdlib.h>
#define MaxSize 1000
int Judge(int result,char op)
{//result只是一个用来判断的标志，只是一个变量名
    if(result)
        switch(op)
        {//operater操作符
            case '+': return 3;
            case '-': return 3;
            case '*': return 5;
            case '/': return 5;
            case '(': return 1;
            case ')': return 6;
        }
    else
        switch(op)
        {
            case '+': return 2;
            case '-': return 2;
            case '*': return 4;
            case '/': return 4;
            case '(': return 6;
            case ')': return 1;
        }
}
void SUFF(char *a)
{//定义一个操作，操作名为SUFF
    int i=0, j=0;
    char b[MaxSize];
    LinkStack *Stack;
    Stack = CreateStack();
    while(a[i])
    {
        if(a[i]>='0'&& a[i]<='9')
        {
            b[j++] = a[i];
            i++;
            continue;
        }
        while( !IsEmpty(Stack) && Judge(0,a[i])<Judge(1,Stack->Next->Date))
            b[j++] = Pop(Stack);
        if(IsEmpty(Stack))
        {
            Push(Stack,a[i]);//Push是入栈操作
            i++;
            continue;
        }
        else if(Judge(0,a[i])==Judge(1,Stack->Next->Date))
            Pop(Stack);
        else if(Judge(0,a[i])>Judge(1,Stack->Next->Date))
            Push(Stack,a[i]);
        i++;
    }
    while(!IsEmpty(Stack))
        b[j++] = Pop(Stack);
    b[j]='\0';
    puts(b);
}
int main()
{
    char a[MaxSize];
    gets(a);
    SUFF(a);
    return 0;
}