c语言实现中缀,后缀,前缀表达式转换并求值

c语言实现中缀,后缀,前缀表达式转换并求值c语言实现中缀,后缀,前缀表达式转换并求值九#include #include #define MAXNUM 100 typedef struct Node//定义存储中缀表达式的结点类型{int data; int data1; char data2; struct Node *next; }Lnode; typedef struct Node2//定义存储前缀表达式的结点类型{int data; int data1; char data2; struct Node2 *next; struct Node2 *prior; }Lnode2; typedef int selemtype1;//定义运算数栈的结点typedef struct//定义运算数栈的类型{selemtype1 *base; selemtype1 *top; }sqstack1; void InitStack1(sqstack1 &s)//新建一个空运算数栈{=(selemtype1 *)malloc(MAXNUM*sizeof(selemtype1));=; if(!) printf(“出错：申请空间失败！\\n”); } void Push1(sqstack1 &s,selemtype1 &e)//运算数栈，入栈：插入元素e为新的栈顶元素{ if(>=MAXNUM) printf(“出错：表达式过长！1\\n”); *++ =e; } void GetTop1(sqstack1 s,selemtype1 &e)//运算数栈，用e返回栈顶元素{e=*(); } void Popopnd1(sqstack1 &s,selemtype1 &e) //运算数栈，退栈：删除栈顶元素，并用e返回其值{e=*--; } int stackempy1(sqstack1 s) //运算数栈，若为空栈返回1，否则返回0 {if(==) return 1; else return 0; } typedef char selemtype2;//定义运算符栈的结点类型typedef struct//定义运算符栈类型{selemtype2 *base; selemtype2 *top; }sqstack2; void InitStack2(sqstack2 &s)//新建一个空运算符栈{=(selemtype2 *)malloc(MAXNUM*sizeof(selemtype2)); =; if(!) printf(“出错：申请空间失败！\\n”); } void Push2(sqstack2 &s,selemtype2 &e)//运算符栈，入栈：插入元素e为新的栈顶元素{ if(>=MAXNUM) printf(“出错：表达式过长！2\\n”); *++ =e; } void GetTop2(sqstack2 s,selemtype2 &e)//运算符栈，用e返回栈顶元素{e=*(); } void Popopnd2(sqstack2 &s,selemtype2 &e) //运算符栈，退栈：删除栈顶元素，并用e返回其值{e=*--; } int stackempy2(sqstack2 s) //运算符栈，若为空栈返回1，否则返回0 {if(==) return 1; else return 0; } void priority(char c,int &i)//确定运算符优先级{if (c==‘*’||c==‘/’||c==‘%’) i=2 ; else if (c==‘+’||c==‘-’) i=1 ; else i=0; } int compare(char a,char b)//比较栈顶元素运算符与外部运算符优先级大小，外部优先级大则返回1，反之返回0 {int in,out; priority(a,in); priority(b,out); if(out>in) return 1; else return 0; } void Operat(sqstack1 &OPND,sqstack2&OPTR) {int num1,num2,num; char c; Popopnd1(OPND,num2);Popopnd1(OPND,num1);Popopnd2(OPTR,c); switch(c) {case ‘+’:num=num1+num2;break; case ‘-’:num=num1-num2;break; case ‘*’:num=num1*num2;break; case ‘/’:num=num1/num2;break; case ‘%’:num=num1%num2;break; } Push1(OPND,num); } void Operatqianzhui(sqstack1 &OPND,sqstack2 &OPTR) {int num1,num2,num; char c; Popopnd1(OPND,num1);Popopnd1(OPND,num2);Popopnd2(OPTR,c); switch(c) {case ‘+’:num=num1+num2;break; case ‘-’:num=num1-num2;break; case ‘*’:num=num1*num2;break; case ‘/’:num=num1/num2;break; case ‘%’:num=num1%num2;break; } Push1(OPND,num); }voidhouzhuiqiuzhi(Lnode *p,int &e) {sqstack1 OPND; //运算数栈sqstack2 OPTR; //运算符栈int n; char c; p=p->next; InitStack1(OPND); InitStack2(OPTR); while(p) {switch(p->data) {case 1:n=p->data1; Push1(OPND,n); break; case 2:c=p->data2; Push2(OPTR,c); Operat(OPND,OPTR); break; default:printf(“结点有误”); brea k; } p=p->next; } Popopnd1(OPND,n); e=n; } void zhongzhui(Lnode *p) {sqstack1 OPND; //运算数栈sqstack2 OPTR; //运算符栈int n; //后缀表达式求值//中缀表达式求值char c,c2; Lnode *first; first=p; p=p->next; InitStack1(OPND); InitStack2(OPTR); while(!stackempy2(OPTR)||p) {while(p) {switch(p->data) {case 1:n=p->data1; Push1(OPND,n); break; case 2:c=p->data2; if(stackempy2(OPTR)) Push2(OPTR,c); else { switch(c){case ‘(‘: Push2(OPTR,c);break; case ‘)’: GetTop2(OPTR,c2); while(c2!=‘(‘) {Operat(OPND,OPTR);GetTop2(OPTR,c2);}Popopnd2(OPTR,c2); break; default: GetTop2(OPTR,c2);if(compare(c2,c)) Push2(OPTR,c); else { Operat(OPND,OPTR); Push2(OPTR,c); } break; } } break; default: printf(“结点有误”); break; } p=p->next; } while(!stackempy2(OPTR))Operat(OPND,OPTR); } Popopnd1(OPND,n); p=first->next; while(p) {if(p->data==1) printf(“%d “,p->data1); if(p->data==2) printf(“%c”,p->data2);p=p->next; } printf(“=%d “,n); }void houzhui(Lnode *p)//中缀表达式转化为后缀表达式{sqstack2OPTR; //运算符栈Lnode *r,*q,*head; int n; char c,c2; InitStack2(OPTR); p=p->next;q=(Lnode*)malloc(sizeof(struct Node)); head=q; while(p) { switch(p->data) {case 1:n=p->data1; r=(Lnode*)malloc(sizeof(struct Node)); q->next=r; q=q->next; q->data=1; q->data1=n; break; case 2:c=p->data2; if(stackempy2(OPTR)) Push2(OPTR,c); else { switch(c) { case ‘(‘: Push2(OPTR,c);break; case ‘)’: Popopnd2(OPTR,c2); while(c2!=‘(‘) { r=(Lnode*)malloc(sizeof(struct Node)); q->next=r; q=q->next; q->data=2; q->data2=c2; Popopnd2(OPTR,c2); } break; default: GetTop2(OPTR,c2); while(!compare(c2,c)){ Popopnd2(OPTR,c2); r=(Lnode*)malloc(sizeof(struct Node)); q->next=r; q=q->next; q->data=2; q->data2=c2; GetTop2(OPTR,c2); }Push2(OPTR,c); break; } } break; default: printf(“结点有误”); break; } p=p->next; } while(!stackempy2(OPTR)){ Popopnd2(OPTR,c2); r=(Lnode*)malloc(sizeof(struct Node)); q->next=r; q=q->next; q->data=2; q->data2=c2; } q->next=NULL; q=head->next; while(q) {if(q->data==1) printf(“%d “,q->data1); if(q->data==2) printf(“%c”,q->data2); q=q->next; } houzhuiqiuzhi(head,n); printf(“=%d “,n); } void qianzhuiqiuzhi(Lnode2 *p,int &e) //前缀表达式求值{sqstack1 OPND; //运算数栈sqstack2 OPTR; //运算符栈int n; char c; Lnode2 *head; head=p; p=p->next; InitStack1(OPND); InitStack2(OPTR); while(p!=head) {switch(p->data) {case 1:n=p->data1; Push1(OPND,n); break; case 2:c=p->data2; Push2(OPTR,c);Operatqianzhui(OPND,OPTR); break; default:printf(“结点有误”); break; } p=p->next; } Popopnd1(OPND,n); e=n; }void qianzhui(Lnode *p)式{sqstack2 OPTR; //运算符栈InitStack2(OPTR); int n; char c,c2; Lnode *first; Lnode2 *q,*head,*r,*head2,*s; first=p; p=p->next; q=(Lnode2*)malloc(sizeof(struct Node2)); //中缀表达式转化为前缀表达//建立存中缀表达式的双向循环链表head=q; while(p) {r=(Lnode2*)malloc(sizeof(struct Node2)); q->next=r; r->prior=q; q=q->next; q->data=p->data; q->data1=p->data1; q->data2=p->data2; p=p->next; } q->next=head; head->prior=q; s=(Lnode2*)malloc(sizeof(struct Node2)); //建立存前缀表达式的双向循环链表head2=s; while(q!=head) {switch(q->data) {case 1:n=q->data1; r=(Lnode2*)malloc(sizeof(struct Node2)); s->next=r; r->prior=s; s=s->next; s->data=1; s->data1=n; break; case 2:c=q->data2; if(stackempy2(OPTR)) Push2(OPTR,c); else { GetTop2(OPTR,c2); if(c2==‘)’) Push2(OPTR,c); else{ switch(c) { case ‘)’:Push2(OPTR,c);break; case ‘(‘: Popopnd2(OPTR,c2); while(c2!=‘)’) { r=(Lnode2*)malloc(sizeof(struct Node2)); s->next=r; r->prior=s; s=s->next; s->data=2; s->data2=c2; Popopnd2(OPTR,c2); } break; default: GetTop2(OPTR,c2); while(!compare(c2,c)){ Popopnd2(OPTR,c2); r=(Lnode2*)malloc(sizeof(struct Node2)); s->next=r; r->prior=s; s=s->next; s->data=2; s->data2=c2; GetTop2(OPTR,c2); } Push2(OPTR,c); break; } } } break; default:printf(“结点有误”); break; }q=q->prior; } while(!stackempy2(OPTR)){ Popopnd2(OPTR,c2); r=(Lnode2*)malloc(sizeof(struct Node2)); s->next=r; r->prior=s; s=s->next; s->data=2; s->data2=c2; } s->next=head2; head2->prior=s; while(s!=head2) {if(s->data==1) printf(“%d “,s->data1);if(s->data==2) printf(“%c”,s->data2); s=s->prior; } qianzhuiqiuzhi(head2,n); printf(“=%d “,n);}int main() { char n[10]; char c; int i,j,k,a,b,z,y,e; Lnode *p,*q,*first; i=0;e=1;a=0;b=1;z=0;y=0;p=(Lnode*)malloc(sizeof(struct Node)); first=p; printf(“请输入中缀表达式”); do { c = getchar(); if(‘0’{ switch (c) { case ‘+’: case ‘-’: case ‘*’: case ‘/’: case ‘%’: case ‘(‘:case ‘)’: case ‘\\n’: { if(n[0]>‘0’&&n[0]next=q; p=p->next; for(k=0;k{ for(j=0;j a=a+(n[k]-’0’)*e; e=1; n[k]=‘0’; } p->data=1; p->data1=a; i=0;a=0; } if(c!=‘\\n’) { if(p->data==2) { if(p->data2!=‘)’&&c!=‘(‘) b=0; } q=(Lnode*)malloc(sizeof(struct Node)); p->next=q; p=p->next; p->data=2; p->data2=c; if(c==‘(‘) z++; if(c==‘)’) y++; } } default: if(c!=‘+’&&c!=‘-’&&c!=‘*’&&c!=‘/’&& c!=‘%’&&c!=‘\\n’&&c!=‘(‘&&c!=‘)’)b=0; } } }while (c != ‘\\n’); if(z!=y) b=0; p->next=NULL; if(b==0) printf(“输入中缀表达式有误”); else {printf(“输入1中缀表达式求值，输入2后缀表达式求值，输入3前缀表达式求值”); scanf(“%d”,&b); if(b==1) zhongzhui(first); if(b==2) houzhui(first); if(b==3) qianzhui(first); } return 1; }。