1322 表达式求值

 

描述

给一些包含加减号和小括号的表达式，求出该表达式的值。表达式中的数值均为绝对值小于 10 的整数。

输入

第一行为表达式的个数 n，以下 n 行每行有一个表达式。每个表达式的长度不超过 20 个字符。

输出

对每个表达式，输出它的值。

样例输入

3

3-(2+3)

-9+8+(2+3)-(-1+4)

0-0

样例输出

-2

1

0

 

 

用两个栈来实现表达式的计算，真的正负号要单独处理

#include <stdio.h>#include <stdlib.h>#include <math.h>#include <string.h>struct op{char c;struct op *before,*next;};struct number{int num;struct number *before,*next;};void push_number(struct number *head2 ,char *ch,struct number *p2,int fu){p2->num=atoi(ch);if (fu){p2->num=-p2->num;}p2->next=NULL;p2->before=head2;head2->next=p2;}void push_op(struct op *head1 ,char ch,struct op *p1){p1->c=ch;p1->next=NULL;p1->before=head1;head1->next=p1;}char pop_op(struct op *head1){struct op *tem;char x=head1->c;head1->before->next=NULL;tem=head1->before;free(head1);head1=tem;return x;}int pop_number(struct number *head2){struct number *tem;int x=head2->num;head2->before->next=NULL;free(head2);head2=tem;return x;}int compare(char ch1, char ch2){if (ch1=='(' && ch2==')'){return 2;}if ((ch1==ch2&&ch1=='^') || ((ch1=='+' || ch1=='-')&&(ch2=='*' || ch2=='/' || ch2=='%')) || ((ch1=='+'||ch1=='-'||ch1=='*'||ch1=='/'||ch1=='%')&&(ch2=='^')) || ch1=='(' || ch2=='(' ){return -1;}else if ((ch1==ch2&&ch1!='^') || ((ch2=='+' || ch2=='-')&&(ch1=='*' || ch1=='/' || ch1=='%')) || ((ch2=='+'||ch2=='-'||ch2=='*'||ch2=='/'||ch2=='%')&&(ch1=='^')) || ch1==')' || ch2==')' ){return 1;}else if ((ch1=='+'&&ch2=='-') || (ch1=='-'&&ch2=='+') || (ch1=='*'&&ch2=='/') || (ch1=='/'&&ch2=='*')){return 1;}else return 0;}int oper(int a,int b,char op){switch (op){case '+': return b+a;case '-': return b-a;case '*': return b*a;case '/': return b/a;case '^': return pow(b,a);case '%': return b%a;}}void main(){   char upset;int pu,n,i,j,k=0,up,m,len,res,num1,num2,num3,flag=0,op_size=0,flag1,flag2,div0,error_ks,unkonwn,fu;struct op *p1,*q1,*head1;struct number *p2,*q2,*head2;char str[100],ch,op1,op2,temp[20],tem_num[20],pre,str1[100],str2[100];scanf("%d",&n);while(upset=getchar())              if(upset=='\n')  break  ;for (i=0;i<n;i++){pre='\0';fu=0;unkonwn=0;error_ks=0;div0=0;op_size=0;gets(str1);if(str1[0]=='\0')continue;        up=0;for(pu=0;str1[pu]!='\0';pu++){  if(str1[pu]!=' ')str2[up++]=str1[pu];}str2[up]='\0';if(str2[0]=='-'){str[0]='0';     up=1;for(pu=0;str2[pu]!='\0';pu++)str[up++]=str2[pu];str[up]='\0';}        else{  up=0;for(pu=0;str2[pu]!='\0';pu++)str[up++]=str2[pu];str[up]='\0';}len=strlen(str);head1=(struct op*)malloc(sizeof(struct op));head2=(struct number*)malloc(sizeof(struct number));head1->next=head1->before=NULL;head2->next=head2->before=NULL;head1->c='\0';for (j=0;j<len;j++){if ((pre<='9'&&pre>='0'&&str[j]=='(') || (pre==')'&&(str[j]<='9' && str[j]>='0')) || (pre==')'&&str[j]=='(')){error_ks=1;break;}if (((pre=='+' || pre=='-' || pre=='*' || pre=='/')&&str[j]=='-') || (pre=='\0'&&str[j]=='-') || (pre=='('&&str[j]=='-')){fu=1;continue;}if (str[j]<='9' && str[j]>='0'){flag=1;tem_num[k++]=str[j];}else        // insert fuhao{if (flag==1){tem_num[k]='\0';p2=(struct number *)malloc(sizeof(struct number));    push_number(head2,tem_num,p2,fu);fu=0;p2->next=head2;    head2=p2;flag=0;k=0;tem_num[0]='\0';}if (op_size==0){p1=(struct op*)malloc(sizeof(struct op));push_op(head1,str[j],p1);p1->next=head1;head1=p1;op_size++;}else{res=compare(head1->c,str[j]);if (res==-1){p1=(struct op*)malloc(sizeof(struct op));push_op(head1,str[j],p1);p1->next=head1;head1=p1;op_size++;}else if (res==2){head1=head1->before;pop_op(head1->next);op_size--;}else if (res==1){head1=head1->before;op1=pop_op(head1->next);op_size--;head2=head2->before;num1=pop_number(head2->next);head2=head2->before;if (head2==NULL){unkonwn=1;break;}num2=pop_number(head2->next);if (op1=='/' && num1==0){printf("Divide 0.\n");div0=1;break;}if (op1=='^' && num1<0){error_ks=1;break;}num3=oper(num1,num2,op1);sprintf(temp,"%d",num3);p2=(struct number *)malloc(sizeof(struct number));push_number(head2,temp,p2,0);p2->next=head2;head2=p2;j--;}}}pre=str[j];}if (error_ks || unkonwn){printf("error.\n");error_ks=unkonwn=0;continue;}if (div0){div0=0;continue;}if (tem_num[0]!='\0'){tem_num[k]='\0';p2=(struct number *)malloc(sizeof(struct number));    push_number(head2,tem_num,p2,fu);p2->next=head2;   head2=p2;flag=0;k=0;tem_num[0]='\0';}flag1=0;flag2=0;q1=head1;k=op_size;if (q1->next==NULL && q1->before!=NULL &&q1->before->c!='\0')q1=q1->before;while(k!=0){ch=q1->c;if (ch=='('){flag1++;}else if (ch==')'){flag2++;}k--;q1=q1->next; }if (flag1!=flag2){printf("error.\n");continue;}while(op_size!=0){head1=head1->before;op1=pop_op(head1->next);op_size--;head2=head2->before;if (head2==NULL){error_ks=1;printf("error");break;}num1=pop_number(head2->next);head2=head2->before;if (head2==NULL){error_ks=1;printf("error.\n");break;}num2=pop_number(head2->next);if (op1=='/' && num1==0){printf("Divide 0.\n");div0=1;break;}if (op1=='^' && num1<0){error_ks=1;printf("error.\n");break;}num3=oper(num1,num2,op1);sprintf(temp,"%d",num3);p2=(struct number *)malloc(sizeof(struct number));push_number(head2,temp,p2,0);p2->next=head2;head2=p2;}if (div0 || error_ks){div0=0;error_ks=0;continue;}printf("%d\n",pop_number(head2));}}