测试案例不可见
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define OK 1 //正确或成功
#define ERROR 0 //错误或失败
typedef int Status;
// 请在这里补充代码，此处可写结构体、函数、全局变量等
/********** Begin *********/
#include <ctype.h>
#define MAX_LEN 256
#define MAX_STACK 100
typedef struct{
char data[MAX_STACK];
int top;
}BracketStack;
typedef struct{
union{
float num_data[MAX_STACK];
char op_data[MAX_STACK];
}data;
int top;
int type;
}Stack;
void InitStack(Stack *s,int type){
s->top=-1;
s->type=type;
}
void InitBracketStack(BracketStack *s){
s->top=-1;
}
Status pushStack(Stack *s,void *val){
if(s->top>=MAX_STACK-1) return ERROR;
s->top++;
if(s->type==0){
s->data.num_data[s->top]=*(float*)val;
}
else if(s->type==1){
s->data.op_data[s->top]=*(char*)val;
}
return OK;
}
Status popStack(Stack *s,void *val){
if(s->top<0) return ERROR;
if(s->type==0){
*(float*)val=s->data.num_data[s->top];
}
else if(s->type==1){
*(char*)val=s->data.op_data[s->top];
}
s->top--;
return OK;
}
Status getTopStack(Stack *s,void *val){
if(s->top<0) return ERROR;
if(s->type==0){
*(float*)val=s->data.num_data[s->top];
}
else if(s->type==1){
*(char*)val=s->data.op_data[s->top];
}
return OK;
}
Status pushBracket(BracketStack *s,char c){
if(s->top>=MAX_STACK-1) return ERROR;
s->data[++s->top]=c;
return OK;
}
Status popBracket(BracketStack *s,char*c){
if(s->top<0) return ERROR;
*c=s->data[s->top--];
return OK;
}
Status getTopBracket(BracketStack *s,char *c){
if(s->top<0)return ERROR;
*c=s->data[s->top];
return OK;
}
int isOperator(char c){
return c=='+'||c=='-'||c=='*'||c=='/'||c=='('||c==')'||c=='['||c==']'||c=='{'||c=='}';
}
int isLeftBracket(char c){
return c=='('||c=='['||c=='{';
}
int isRightBracket(char c){
return c==')'||c==']'||c=='}';
}
char matchBracket(char right){
switch(right){
case')':return '(';
case']':return '[';
case'}':return '{';
default:return 0;
}
}
int getPriority(char op){
if(isLeftBracket(op)) return 0;
switch(op){
case'+':
case'-':return 1;
case'*':
case'/':return 2;
default:return -1;
}
}
void normalizeExpr(char *src,char *dst){
int j=0;
int len=strlen(src);
for(int i=0;i<len;i++){
if(src[i]==' '||src[i]=='\t')continue;
if(src[i]=='['||src[i]=='{'){
dst[j++]='(';
}
else if(src[i]==']'||src[i]=='}'){
dst[j++]=')';
}
else{
dst[j++]=src[i];
}
}
dst[j]='\0';
}
Status checkExprValid(char *expr){
BracketStack bStack;
InitBracketStack(&bStack);
int len=strlen(expr);
int lastIsOp=1;
int lastIsBracket=1;
int dotCount=0;
for(int i=0;i<len;i++){
char c=expr[i];
if(c==' '||c=='\t')continue;
if(!((c>='0'&&c<='9')||isOperator(c)||c=='.')){
return ERROR;
}
if(isLeftBracket(c)){
pushBracket(&bStack,c);
lastIsOp=1;
lastIsBracket=1;
dotCount=0;
continue;
}
if(isRightBracket(c)){
char top;
if(getTopBracket(&bStack,&top)==ERROR||top!=matchBracket(c)){
return ERROR;
}
popBracket(&bStack,&top);
lastIsOp=0;
lastIsBracket=0;
dotCount=0;
continue;
}
if(isOperator(c)&&!isLeftBracket(c)&&!isRightBracket(c)){
if(lastIsOp&&!(c=='-'&&(lastIsBracket||i==0))){
return ERROR;
}
lastIsOp=1;
lastIsBracket=0;
dotCount=0;
continue;
}
if((c>='0'&&c<='9')||c=='.'){
if(c=='.'){
dotCount++;
if(dotCount>1)return ERROR;
if(i==0||(i+1>=len||!isdigit(expr[i+1])))return ERROR;
}
lastIsOp=0;
lastIsBracket=0;
continue;
}
}
if(bStack.top!=-1)return ERROR;
if(lastIsOp)return ERROR;
return OK;
}
Status calculateBinary(float a,char op,float b,float *res){
switch(op){
case'+':*res=a+b;
break;
case'-':*res=a-b;
break;
case'*':*res=a*b;
break;
case'/':
if(b<1e-6&&b>-1e-6)return ERROR;
*res=a/b;
break;
default:return ERROR;
}
return OK;
}
/********** End **********/
Status calculator(char line[],float &value)
//line:表达式，value:存表达式的值
//函数功能：计算表达式line的值
//如果表达式line的值被正确计算，返回OK；否则返回Error
{
// 请在这里补充代码
/********** Begin *********/
if(checkExprValid(line)==ERROR){
return ERROR;
}
char normExpr[MAX_LEN];
normalizeExpr(line,normExpr);
Stack numStack,opStack;
InitStack(&numStack,0);
InitStack(&opStack,1);
int i=0;
int len=strlen(normExpr);
while(i<len){
char c=normExpr[i];
if(c==' '||c=='\t'){
i++;
continue;
}
if(isdigit(c)||(c=='-'&&(i==0||normExpr[i-1]=='('||isOperator(normExpr[i-1])&&!isRightBracket(normExpr[i-1])))||(c=='.'&&i>0&&isdigit(normExpr[i-1]))){
int isNegative=0;
float num=0.0f;
int decimal=0;
float decFactor=0.1f;
if(c=='-'){
isNegative=1;
i++;
if(i>=len)return ERROR;
c=normExpr[i];
}
while(i<len&&isdigit(normExpr[i])){
num=num*10+(normExpr[i]-'0');
i++;
}
if(i<len&&normExpr[i]=='.'){
decimal=1;
i++;
while(i<len&&isdigit(normExpr[i])){
num+=(normExpr[i]-'0')*decFactor;
decFactor*=0.1f;
i++;
}
if(decimal&&(i==len||!isdigit(normExpr[i-1])))return ERROR;
}
if(isNegative)num=-num;
if(!pushStack(&numStack,&num))return ERROR;
continue;
}
if(isOperator(c)){
if(isLeftBracket(c)){
char op='(';
if(!pushStack(&opStack,&op)) return ERROR;
i++;
}else if(isRightBracket(c)){
char op;
while(getTopStack(&opStack,&op)==OK&&op!='('){
float b,a,res;
if(!popStack(&numStack,&b)||!popStack(&numStack,&a))return ERROR;
if(!calculateBinary(a,op,b,&res))return ERROR;
if(!pushStack(&numStack,&res))return ERROR;
popStack(&opStack,&op);
}
if(!popStack(&opStack,&op)||op!='(')return ERROR;
i++;
}
else{
char topOp;
while(getTopStack(&opStack,&topOp)==OK&&getPriority(topOp)>=getPriority(c)){
float b,a,res;
if(!popStack(&numStack,&b)||!popStack(&numStack,&a))return ERROR;
if(!calculateBinary(a,topOp,b,&res))return ERROR;
if(!pushStack(&numStack,&res))return ERROR;
popStack(&opStack,&topOp);
}
if(!pushStack(&opStack,&c))return ERROR;
i++;
}
continue;
}
}
char op;
while(getTopStack(&opStack,&op)==OK){
float b,a,res;
if(!popStack(&numStack,&b)||!popStack(&numStack,&a))return ERROR;
if(!calculateBinary(a,op,b,&res))return ERROR;
if(!pushStack(&numStack,&res))return ERROR;
popStack(&opStack,&op);
}
if(numStack.top!=0)return ERROR;
getTopStack(&numStack,&value);
return OK;
/********** End **********/
}
Status readFile(char filename[])
//filename：文件名(txt文件)
//函数功能：读入filename文件中的表达式（一行存储一个表达式，文件中可能有多行），针对每个表达式，调用calculator执行表达式的计算
//输出表达式的计算结果，输出格式如下：
//（1）若表达式的值被正确计算，则输出格式为：printf("表达式%s的计算结果为：%.2f\n",X,XX);
//（2）若表达式错误，不能被正确计算，则输出格式为：printf("表达式%s错误\n",X);
//若文件中的所有表达式都被处理则函数返回OK，否则返回ERROR
{
// 请在这里补充代码
/********** Begin *********/
FILE *fp=fopen(filename,"r");
if(fp==NULL)return ERROR;
char line[MAX_LEN];
while(fgets(line,MAX_LEN,fp)!=NULL){
size_t len=strlen(line);
if(len>0){
if(line[len-1]=='\n')line[len-1]='\0';
if(len>1&&line[len-2]=='\r')line[len-2]='\0';
}
if(strlen(line)==0)continue;
float value;
if(calculator(line,value)==OK){
printf("表达式%s的计算结果为：%.2f\n",line,value);
}
else{
printf("表达式%s错误\n",line);
}
}
fclose(fp);
return OK;
/********** End **********/
}
int main()
{
char filename[100];
//请输入要读取的文件名:
scanf("%s", filename);
if(!readFile(filename)){
printf("输入文件不存在或I/O错误");
}
return 0;
}
