栈的应用之中缀表达式转化为后缀表达式(逆波兰表达式)

 1 #include<stdio.h>
 2 #include<stdlib.h>
 3 
 4 #define OK         1
 5 #define ERROR         0
 6 #define STACK_INIT_SIZE 20
 7 #define STACK_INCREMENT 10
 8 
 9 typedef char Elemtype;  10 typedef int Status;  11 
 12 typedef struct StackNode{  13     Elemtype* base;  14     Elemtype* top;  15     int stackSize;  16 }StackNode;  17 typedef struct StackNode* Stack;  18 
 19 Status InitStack(Stack s){  20     s->base = (Elemtype*)malloc(sizeof(Elemtype) * STACK_INCREMENT);  21     if(! s->base){  22         return ERROR;  23  }  24     s->top = s->base;  25     s->stackSize = STACK_INIT_SIZE;  26     return OK;  27 }  28 Status Pop(Stack s,Elemtype* value){  29     if(s->base == s->top){  30         printf("pop ERROR\n");  31         return ERROR;  32  }  33     *value = *(--(s->top));  34     return OK;  35 }  36 Status Push(Stack s, Elemtype value){  37     if(s->top - s->base == s->stackSize){  38         s->base = (Elemtype*)realloc(s->base,sizeof(Elemtype) * (STACK_INIT_SIZE + STACK_INCREMENT));  39         if(! s->base)  40             return ERROR;  41         s->top = s->base + STACK_INIT_SIZE;  42         s->stackSize = STACK_INCREMENT + STACK_INIT_SIZE;  43  }  44     *(s->top) = value;  45     s->top++;  46     return OK;  47 }  48 int StackLength(Stack s){  49     return s->top - s->base;  50 }  51 //test
 52 Status ShowStack(Stack s){  53     while(s->top != s->base){  54         printf("%c ",*(--(s->top)));  55  }  56     printf("\n");  57 }  58 
 59 Status Infix2Postfix(){            //将中缀表达式转化为后缀表达式
 60  StackNode s;  61     InitStack(&s);  62     char c;  63     char c1;  64     printf(" Please Enter Infix expression\n");  65     printf(" -------note: number separeted by space,end of '#'\n\n");  66     scanf("%c", &c);  67     /* Note:如果是数字： 直接输出控制台；  68  * 如果是*，/，（: 直接Push  69  * 如果是+，-： 则要将*,/,+,-都进行Pop，直到stack为空或者是遇到了'('  70  * 如果是')'： 将在遇到'('之前的所有的都要Pop  71  * */
 72     while('#' != c){  73         while(c >= '0' && c <= '9'){     //如果是数字，则直接输出
 74             printf("%c", c);  75             scanf("%c", &c);  76             if( c < '0' || c > '9'){  77                 printf("%c", ' ');  78                 break;  79  }  80  }  81         if('+' == c || '-' == c){    //如果是 + 或者是 -
 82             if(!StackLength(&s)){        //如果stack为空的话，直接Push
 83                 Push(&s,c);  84  }  85             else{            //不为空的话需要Pop进行比较/+-*都需要Pop
 86                 Pop(&s,&c1);  87                 while( '(' != c1 ){  88                     printf("%c ", c1);  89                     if(StackLength(&s) == 0){  90                         break;  91  }  92                     else
 93                         Pop(&s, &c1);  94  }  95                 if( '(' == c1 )  96                     Push(&s, c1);  97                 Push(&s, c);  98  }  99  } 100         else if('*' == c || '/' == c || '(' == c){    //如果是*或者是/
101             Push(&s, c); 102  } 103         else if( ')' == c ){ 104             Pop(&s,&c1); 105             while( '(' != c1){ 106                 printf("%c ", c1); 107                 Pop(&s, &c1); 108  } 109  } 110         else if( '#' == c ){ 111             break; 112  } 113         else{ 114             printf("Input Is ERROR!\n"); 115             return ERROR; 116  } 117         scanf("%c", &c); 118  } 119 
120     while(StackLength(&s)){ 121         Pop(&s,&c1); 122         printf("%c ", c1); 123  } 124     return OK; 125 } 126 int main(){ 127  Infix2Postfix(); 128 /*
129  Stack s; 130  InitStack(s); 131  Push(s,'a'); 132  Push(s,'r'); 133  Push(s,'e'); 134  Push(s,'d'); 135  ShowStack(s); 136 */
137     return 0; 138 }