替换文本中，指定行的内容

#include <iostream>
#include <fstream>
#include <stdlib.h>
#include <string>
#include <string.h>
using namespace std;
void saveConfigFile( string filePath, string keyStr,string replaceStr){
    fstream file(filePath.c_str());  
    string line;  
    int n, count = 0;  
    //create a temp file  
    ofstream outfile("1.conf", ios::out | ios::trunc);  
    //read the original file  
    while (!file.eof())  
    {  
        getline(file, line);//read one line  
        //judge the line just read is the line to process  
        if (strstr(line.c_str(), keyStr.c_str()))
        {  
            outfile<<replaceStr<<endl;
        }  
        else  
            outfile << line << endl;  
    }  
    outfile.close();  
    file.close();  
    ofstream outfile1(filePath.c_str(), ios::out | ios::trunc);  
    fstream file1("1.conf");  
    //write the temp file to the original file  
    while (!file1.eof())  
    {  
        getline(file1, line);  
        outfile1 << line << endl;  
    }  
    outfile1.close();  
    file1.close();  
    //delete the temp file  
    system("rm 1.conf");  
    
}

main(){
    string filePath ="a.conf";
    saveConfigFile("a.conf","sv-as-startup","[VOL_ATTRIBUTE]sv-as-startup,3,45,1,9;");
    
}

a.conf
#[VOL_DEFAULT_ATTRI]音频流名字,最小音量,最大音量,步长,默认值;
[VOL_ATTRIBUTE]sv-as-tts,0,10,1,6;
[VOL_ATTRIBUTE]sv-as-asr,0,10,1,6;
[VOL_ATTRIBUTE]sv-as-music,0,35,1,10;
[VOL_ATTRIBUTE]sv-as-link-phone,0,10,1,6;
[VOL_ATTRIBUTE]sv-as-link-ring,0,10,1,6;
[VOL_ATTRIBUTE]sv-as-link-asr,0,10,1,6;
[VOL_ATTRIBUTE]sv-as-link-navi,0,10,1,6;
[VOL_ATTRIBUTE]sv-as-bt-ring,0,10,1,6;
[VOL_ATTRIBUTE]sv-as-asr-beep,0,10,1,6;
[VOL_ATTRIBUTE]sv-as-bt-phone,0,10,1,6;
[VOL_ATTRIBUTE]sv-as-key,0,100,10,60;
[VOL_ATTRIBUTE]sv-as-startup,3,45,1,9;
[VOL_ATTRIBUTE]sv-as-field,0,24,1,12;
[VOL_ATTRIBUTE]sv-as-eq,0,24,1,12;
[VOL_ATTRIBUTE]sv-as-sdvc,0,7,1,0;


#[VOL_GROUPS]组内,音量绑定在一起,一个变化，组内audio id的音量跟着变化。
#[VOL_GROUPS]10,15,16;
#[VOL_GROUPS]9,21;