栈的应用之表达式求值4页

1、栈的应用之表达式求值程序代码如下：#include"stdio.h"#include"stdlib.h"#define MAXSIZE 100#define ERROR 0#define OK 1#define OVERFLOW -1typedef struct /栈的定义 char *base; char *top; int stacksize;SqStack;int InitStack(SqStack &S) /栈的初始化 S.base=new charMAXSIZE; if(!S.base) exit(OVERFLOW); S.top=S.

2、base; S.stacksize=MAXSIZE; return OK;char Push(SqStack &S,char e) /入栈 if(S.top-S.base=S.stacksize) return ERROR; *S.top+=e; return OK;char Pop(SqStack &S,char &e) /出栈 if(S.top=S.base) return ERROR; e=*-S.top; return OK;int GetTop(SqStack S) /取栈顶元素 if(S.top!=S.base) return *(S.top-1);char

3、 In(char c) /判断读入字符是否为运算符 if('0'<=c&&c<='9')return 0;elsereturn 1;char Precede(char c1,char c2) /运算符的优先级 int i,j;char pre77='>','>','<','<','<','>','>','>','>','<&#

4、39;,'<','<','>','>','>','>','>','>','<','>','>','>','>','>','>','<','>','>','<','<&#

5、39;,'<','<','<','=','0','>','>','>','>','0','>','>','<','<','<','<','<','0','='switch(c1)case'+':

6、i=0;break;case'-': i=1;break;case'*': i=2;break;case'/': i=3;break;case'(': i=4;break;case')': i=5;break;case'#': i=6;break;switch(c2)case'+': j=0;break;case'-': j=1;break;case'*': j=2;break;case'/': j=3;break;case'(

7、': j=4;break;case')': j=5;break;case'#': j=6;break;return preij;char Operate(char a,char theta,char b) /运算函数 int result; switch(theta) case'+':result=(a-48)+(b-48);break; case'-':result=(a-48)-(b-48);break; case'*':result=(a-48)*(b-48);break; case'/

8、9;:result=(a-48)/(b-48);break; return result+0;char EvaluateExpression() SqStack OPTR; SqStack OPND; InitStack(OPTR); InitStack(OPND); Push(OPTR,'#'); char x,w,theta,a,b; w=getchar(); while(w!='#'|GetTop(OPTR)!='#') if(!In(w) Push(OPND,w); w=getchar(); else switch(Precede(GetTop(OPTR),w) case'<': Push(OPTR,w); w=getchar(); break; case'=': Pop(OPTR,x); w=getchar(); break; case'>': Pop(OPTR,theta); Pop(OPND,b); Pop(OPND,a); /a是第一运算数，b是第二运算数 Push(OPND,Operate(a,theta,b); break; return(GetTop(OPND);void main() int c; printf(&qu