读取文件 删除注释的C++程序

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我有朋友向我求助写一个读取文件然后删掉注释的程序，也顺便练练手。

内容是在content里面。

下面的只是读到了content然后显示，没有改动原来文件的内容。

#include<iostream>
#include<algorithm>
#include<cstdio>
#include <stack> 
#include <fstream> 
#include <cstring>
#include <string>
using namespace std;

int main(){ 
	//read all content into content string. 
	ifstream rfile;
    
    string filename="1.txt";
    string contents;
    string line;
    rfile.open(filename.c_str());
    
    while(getline(rfile,line)){
    	contents.append("\n");
        contents.append(line);
    }
    cout<<contents<<endl;
    cout<<"length of this file is "<<contents.length()<<"charactors!"<<endl<<endl<<endl;
    cout<<"After deleting notation:"<<endl; 
    
    //manipulate content string
    
    int i=0;
    while(i<contents.length()-1){
    	//delete // type notation
    	if(contents[i]=='/'&&contents[i+1]=='/'){
    		while(contents[i]!='\n'&&i<contents.length()){
    			contents[i]=' ';
    			i++;
			}
		}//  delete /**/ type notation
		else if(contents[i]=='/'&&contents[i+1]=='*'){
			int startIndex=i;
			i+=2;//move to the charactor after *.
			while(i<contents.length()&&!(contents[i]=='*'&&contents[i+1]=='/'))
				i++;
			
			if(i==contents.length()-1){
				cout<<"illegal notation format!"<<endl;
				break;
			}
			for(int j=startIndex;j<=i+1;j++) contents[j]=' ';
			
			
		}// just move forward
		else i++;
	}
    
    for(int index=0;index<contents.length();index++)
    	cout<<contents[index];
    cout<<endl;
    return 0;
		
}