替换遇到的第一个数字

#include<iostream>

#include<fstream>

#include<string>

using namespace std;

int main(){

ofstream write;

write.open("2.txt");

ifstream read;

 read.open("11.txt");

string s;int i=0;

for(int k=0;k<29;k++){

while(getline(read,s)){

//    if(s[0]==' '){break;}

     for(i=0;i<s.length();i++){

       if(s[i]>=48&&s[i]<=57){

        write<<s.substr(0,i)<<k<<s.substr(i+1,s.length())<<endl;

        break;

       }

     }

}

read.close();

read.open("11.txt");

}

write.close();

return 0;

}