1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <string.h>
4 #define INIT_STACK_SIZE 100
5 typedef struct
6 {
7 char * chOperator;
8 int dwtop;
9 }OPND;
10
11 void InitStack(OPND *);
12 char Pop(OPND *);
13 void Push(OPND *,char );
14 char GetTop(OPND);
15
16 char ComparePri(char op1,char op2);
17 void printStack(OPND);
18
19 char stringBuffer[128] = {‘\0‘};
20 char stringValue[128] = {‘\0‘};
21 int main()
22 {
23 OPND opnd;
24 int N = 0;
25 char ch ,*strValue,*strBuffer;
26 scanf("%d",&N);
27 getchar();
28 while(N--){
29
30 strValue = stringValue;
31 strBuffer = stringBuffer;
32
33 memset(stringValue,0,128*sizeof(char));
34 memset(stringBuffer,0,128*sizeof(char));
35
36 gets(stringBuffer);
37 InitStack(&opnd);
38 Push(&opnd,‘#‘);
39
40 ch = *strBuffer++;
41 while(ch != ‘#‘ || GetTop(opnd) != ‘#‘){
42 if((ch >= ‘a‘ && ch <= ‘z‘)||(ch >= ‘A‘ && ch <= ‘Z‘)) {
43 *strValue = ch;
44 strValue++;
45 ch = *(strBuffer++);
46 }
47 else
48 switch(ComparePri(GetTop(opnd),ch)){
49 case ‘<‘ : Push(&opnd,ch); ch = *(strBuffer++); break;
50 case ‘=‘ : Pop(&opnd); ch = *(strBuffer++); break;
51 case ‘>‘ : *strValue = Pop(&opnd); strValue++; break;
52 }
53 }
54 puts(stringValue);
55 }
56 return 0;
57 }
58 void InitStack(OPND *S)
59 {
60 S->chOperator = (char *)malloc(INIT_STACK_SIZE * sizeof(char));
61 if(!S->chOperator) exit(1);
62 S->dwtop = 0;
63 }
64 void Push(OPND *S,char ch)
65 {
66 *(S->chOperator + S->dwtop) = ch;
67 S->dwtop++;
68 }
69 char Pop(OPND *S)
70 {
71 S->dwtop--;
72 return *(S->chOperator + S->dwtop);
73 }
74 char ComparePri(char op1,char op2)
75 {
76 if((op1 == ‘+‘ || op1 == ‘-‘)&&(op2 == ‘*‘ || op2 == ‘/‘)) return ‘<‘;
77 else if((op1 == ‘(‘ && op2 == ‘)‘)||(op1 == ‘#‘ && op2 == ‘#‘)) return ‘=‘;
78 else if(op1 == ‘(‘ || op1 == ‘#‘ || op2 == ‘(‘) return ‘<‘;
79 else return ‘>‘;
80 }
81 void printStack(OPND opnd)
82 {
83 while(opnd.dwtop){
84 opnd.dwtop--;
85 printf("%c",*(opnd.chOperator + opnd.dwtop));
86 }
87 }
88 char GetTop(OPND opnd)
89 {
90 return *(opnd.chOperator + opnd.dwtop -1);
91 }
[栈和队列]从中缀向后缀转换表达式,码迷,mamicode.com
时间： 2024-11-03 21:01:11