表达式求值

问题描述：使用键盘输入表达式，计算表达式的值并输出；将表达式转化成后缀表达式输出，利用后缀表达式求表达式的值并输出。

测试数据：

3*（7-2）

2*（6+2*（3+6*（6+6）））+（6+6）*3+2

8/（9-9）

#include<stdio.h>#include<stdlib.h>#define MAX 30typedef struct tagNode{char data;struct tagNode *next;}Node,*LinkList;//用结构体数组实现顺序栈typedef struct tagStack1{char S[MAX];int top;}Stack1;   //存储运算符typedef struct tagStack2{float S[MAX];int top;}Stack2;   //存储运算数int SEmpty1(Stack1 s)     //判运算符栈空{    if(s.top==-1)return 1;    else return 0;}//SEmpty1int SEmpty2(Stack2 s)     //判运算数栈空{    if(s.top==-1)return 1;    else return 0;}//SEmpty2 int Push1(Stack1 *s,char x)     //运算符入栈{    if(s->top==MAX-1)return 0;   //栈满不能入栈，返回0    else{        s->top++;        s->S[s->top]=x;         //栈不满则压入数据x        return 1;               //进栈成功，返回1    } }//Push1int Push2(Stack2 *s,float x)     //运算数入栈{    if(s->top==MAX-1)return 0;      else{        s->top++;        s->S[s->top]=x;           return 1;              } }//Push2int Pop1(Stack1 *s,char *x)       //运算符出栈{    if(SEmpty1(*s))return 0;      //若栈空不能出栈，返回0    else{*x=s->S[s->top];        s->top--;        return 1;                 //出栈成功，返回1    }}//Pop1int Pop2(Stack2 *s,float *x)      //运算数出栈{    if(SEmpty2(*s))return 0;          else{*x=s->S[s->top];        s->top--;        return 1;    }}//Pop2char Precede(char a,char b)        //优先级判断{int i,c,d;static char bijiao[7][7]={'>','>','<','<','<','>','>',                              '>','>','<','<','<','>','>',                              '>','>','>','>','<','>','>',                              '>','>','>','>','<','>','>',                              '<','<','<','<','<','=',' ',                              '>','>','>','>',' ','>','>',                              '<','<','<','<','<',' ','='};char h[7]={'+','-','*','/','(',')','#'};for(i=0;i<=6;i++){if(a==h[i])c=i;if(b==h[i])d=i;}return bijiao[c][d];}//Precedechar ReadTop1(Stack1 s)        //读运算符栈顶元素{    if(SEmpty1(s))return 0;    else return s.S[s.top];    //读栈顶元素，但指针没有移动}//ReadTop1float ReadTop2(Stack2 s)       //读运算数栈顶元素{    if(SEmpty2(s))return 0;    else return s.S[s.top];}//ReadTop1float Count(float m,char the,float n,int *d)      //运算函数{switch(the){case '*':return m*n;case '+':return m+n;case '-':return m-n;case '/':if(n!=0)return m/n;else *d=*d+1;break;}//switchreturn 0;}//Countvoid Operate1(LinkList L){int d=0;char x,theta;float a,b;LinkList p=L->next;Stack1 OPTR;Stack2 OPND;         //OPTR为运算符栈，OPND为操作数栈 OPTR.top=0;OPND.top=-1;OPTR.S[0]='#';while(p->data!='#'||ReadTop1(OPTR)!='#'){if(p->data>='0'&&p->data<='9'){Push2(&OPND,(float)(p->data-48));p=p->next;}//ifelse{            switch(Precede(ReadTop1(OPTR),p->data)){case '<'://栈顶元素优先级低Push1(&OPTR,p->data);p=p->next;break;case '='://脱括号Pop1(&OPTR,&x);p=p->next;break;case '>'://退栈并将运算结果入栈Pop1(&OPTR,&theta);Pop2(&OPND,&b);Pop2(&OPND,&a);Push2(&OPND,Count(a,theta,b,&d));break;}//switch}//else}//whileif(d!=0){printf("ERROR!!!\n");return;}else printf("=%.2f\n",ReadTop2(OPND));}//Operate1void Operate2(LinkList L){int i,j,d=0;float a,b;Stack1 OPTR1;Stack2 OPND1,OPND3;//OPND3用作对后缀表达式求值LinkList p=L->next;OPTR1.top=0;OPND1.top=-1,OPND3.top=-1;OPTR1.S[0]='#';while(p->data!='#'||ReadTop1(OPTR1)!='#'){if(p->data>='0'&&p->data<='9'){Push2(&OPND1,(float)(p->data-48));Push2(&OPND3,(float)(p->data-48));p=p->next;}//ifelse{            switch(Precede(ReadTop1(OPTR1),p->data)){case '<'://栈顶元素优先级低Push1(&OPTR1,p->data);p=p->next;break;case ' ':p=p->next;break;case '>'://输出栈中元素，并将栈清空for(i=0;i<=OPND1.top;i++)printf("%.0f ",OPND1.S[i]);OPND1.top=-1;if(p->data==')'&&(p->next->data=='*'||p->next->data=='/')){j=OPTR1.top;while(OPTR1.S[j]!='('){printf("%c ",OPTR1.S[j]);Pop2(&OPND3,&b);Pop2(&OPND3,&a);//对后缀表达式进行求值        Push2(&OPND3,Count(a,OPTR1.S[j],b,&d));j--;}//whileOPTR1.top=j-1;}//ifelse{    for(j=OPTR1.top;j>=1;j--){if(OPTR1.S[j]!='('){        printf("%c ",OPTR1.S[j]);        Pop2(&OPND3,&b);Pop2(&OPND3,&a);//对后缀表达式进行求值    Push2(&OPND3,Count(a,OPTR1.S[j],b,&d));}}//for    OPTR1.top=0;}//elseif(p->data!=')')Push1(&OPTR1,p->data);if(p->data!='#')p=p->next;break;}//switch}//else}//whileif(d!=0){printf("ERROR!!!\n");return;}    else printf("=%.2f\n",ReadTop2(OPND3));}//Operate2int main(){char i;LinkList L,p,s;p=L=(LinkList)malloc(sizeof(Node));printf("请输入中缀表达式(以#结束):\n");while(p->data!='#'){s=(LinkList)malloc(sizeof(Node));scanf("%c",&s->data);p->next=s;p=s;}p->next=NULL;p=L->next;while(p->data!='#'){printf("%c",p->data);p=p->next;}scanf("%c",&i);Operate1(L);printf("转化为后缀表达式并求值为(输入Y or N):\n");scanf("%c",&i);switch(i){    case 'Y':Operate2(L);break;case 'N':printf("谢谢使用!\n");break;}return 0;}//main