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 }
