就是一個簡單地計算器，能處理一串輸入程序是沒有什么問題的，但是我看不懂為什么expr（）函數里的value會顯示出來？？expr（）里面不是沒有return value這句嗎疑惑啊 哪位指點一下#include <iostream>#include<cstdlib>#include<cctype>using namespace std;void eatspaces(char* str);double expr(char* str);double term(char* str,int& index);double number(char* str,int& index);const int MAX =80;int main(){char buffer[MAX]={0};cout<<endl<<"Welcome!"<<endl<<"Enter an expression,or an empty line to quit."<<endl;for(;;){cin.getline(buffer,sizeof buffer);eatspaces(buffer);if(!buffer[0])return 0;cout<<"="<<expr(buffer)<<endl;}}void eatspaces(char* str){int i=0;int j=0;while((*(str+i)=*(str+j++))!='\0')if(*(str+i)!=' ')i++;return;}//Function to evaluate an arithmetic expressiondouble expr(char* str){double value=0.0;int index=0;value=term(str,index);for(;;)switch(*(str+index++)){case '\0':return value;case '+':value+=term(str,index);break;case '-':value-=term(str,index);break;default:cout<<endl<<"Arrrgh!*#!! There's an error"<<endl;exit(1);}}//Function to get the value of a termdouble term(char* str,int& index){double value=0.0;value=number(str,index);while((*(str+index)=='*')||(*(str+index)=='/')){if(*(str+index)=='*')value *=number(str,++index);if(*(str+index)=='/')value /=number(str,++index);}return value;}//Function to recognize anumber in a stringdouble number(char* str,int& index){double value =0.0;while(isdigit(*(str+index)))value=10*value+(*(str+index++)-'0');if(*(str+index)!='.')return value;double factor=1.0;while(isdigit(*(str+(++index)))){factor *=0.1;value=value+(*(str+index)-'0')*factor;}return value;}程序是沒有什么問題的，當時我看不懂為什么expr（）函數里的value會顯示出來？？expr（）里面不是沒有return value這句嗎疑惑啊 哪位指點一下