1 #include<stdio.h>
  2 #include<stdlib.h>
  3 #define Stack_Size 100
  4 #define StackIncrement 10
  5 #define Ok 1
  6 #define Error 0
  7 #define True 1
  8 #define False 0
  9 #define Overflow -2
 10 typedef int status;
 11 //字符栈的操作
 12 typedef struct
 13 {
 14   char *base;
 15   char *top;
 16   int stacksize;
 17 }SqStack;
 18 status InitStack(SqStack &S)
 19 {
 20   S.base=(char *)malloc(Stack_Size*sizeof(char));
 21   if(!S.base)  exit(Overflow);
 22   S.top=S.base;
 23   S.stacksize=Stack_Size;
 24   return Ok;
 25 }
 26 status StackEmpty(SqStack &S)
 27 {
 28   if(S.top==S.base)
 29   return True;
 30   return False;
 31 }
 32 status GetTop(SqStack S,char &e)
 33 {
 34     if(S.top==S.base)  return Error;
 35     e=*(S.top-1);
 36     return Ok;
 37 }
 38 status Push(SqStack &S,char e)
 39 {
 40   if((S.top-S.base)==S.stacksize)
 41   {
 42     S.base=(char *)realloc(S.base,(S.stacksize+StackIncrement)*sizeof(char));
 43     if(!S.base)  exit(Overflow);
 44     S.top=S.base+S.stacksize;
 45     S.stacksize+=StackIncrement;
 46   }
 47   *S.top++=e;
 48   return Ok;
 49 }
 50 status Pop(SqStack &S,char &e)
 51 {
 52   if(S.top==S.base)  return Error;
 53   e=*--S.top;
 54   return Ok;
 55 }
 56 //转化的操作过程
 57 static int i=0;
 58 status Pass(char *s,char c)
 59 {
 60     s[i]=c;
 61     i++;
 62     return Ok;
 63 }
 64 status In(char c)
 65 {
 66   switch(c)
 67   {
 68     case '+':
 69     case '-':
 70     case '*':
 71     case '/':
 72     case '(':
 73     case ')':
 74     case '#':return True;
 75     default :return False;
 76   }
 77 }
 78 int Precede(char t1,char t2)
 79  {
 80    int f=0;
 81    switch(t1)
 82    { case '+':
 83      case '-':if(!(t2=='('||t2=='*'||t2=='/'))
 84                 f=1;
 85               break;
 86      case '*':
 87      case '/':if(t2!='(')
 88                 f=1;
 89               break;
 90      case '(':if(t2=='#')
 91               {printf("缺乏左括号\n");
 92                exit(Overflow);}
 93                break;
 94      case ')':if(t2!='(')
 95               f=1;
 96               else
 97               {
 98                       printf("括号不匹配\n");
 99                     exit(Overflow);
100               }
101    }
102    return f;
103  }
104 status Converse(char *s)
105 {
106     SqStack OPTR;
107     char ch,x,c=getchar();
108     InitStack(OPTR); Push(OPTR,'#');
109     while(!StackEmpty(OPTR))
110     {
111         if(!In(c))
112             Pass(s,c);
113         else
114         switch(c)
115         {
116             case '(': Push(OPTR,c);break;
117             case ')': Pop(OPTR,ch);while(ch!='('){Pass(s,ch);Pop(OPTR,ch);}break;
118             default :
119                       while(GetTop(OPTR,ch)&&Precede(ch,c))
120                       {
121                           Pass(s,ch);Pop(OPTR,ch);
122                       }
123                       if(c!='#')
124                       Push(OPTR,c);
125         }
126         if(c!='#')
127             c=getchar();
128         else
129         {
130             Pop(OPTR,ch);
131             Pass(s,ch);
132         }
133     }
134     s[i]='\0';
135     return Ok;
136 }
137 //主函数
138 status main()
139 {
140     char s[100];
141     puts("请输入算术表达式：");
142     Converse(s);
143     puts("转化后的后缀表达式为：");
144     puts(s);
145     return Ok;
146 }