从文件行每行读取一个字符串，仅读取第一个单词

Question

I got this Code from here .

#include <iostream> 
#include <fstream> 
#include <string> 
#include <limits> // numeric_limits 

void print_line( const std::string& filename, int lnNo ) 
{ 
    using namespace std; 
    ifstream file( filename.c_str() ); 
    if( !file.is_open() ) 
    { 
        cerr << "Fehler beim Oeffnen der Datei " << filename << endl; 
        return 0; 
    } 
    for( ; lnNo > 1; --lnNo ) 
        file.ignore( numeric_limits< streamsize >::max(), '\n' ); 
    string line; 
    if( !getline( file, line ) ) 
    { 
        cerr << "Fehler beim Lesen aus der Datei " << filename << endl; 
        return 0; 
    } 
    cout << line << endl; 
} 

int main () 
{ 
    using namespace std; 
    for( int lnNo; cin >> lnNo; ) 
        print_line( "input.txt", lnNo ); 
    return 0; 
}

This reads in a whole line specified by lnNo . What do I have to change when I just want to read in the first word per line?

Thanks in advance.

Answer 1

Thanks to your response, Joachim Pileborg, I could answer my question by myself. I added the two lines to the end of print_line :

int strpos = line.find(" ");
string input = line.substr(0, strpos);
cout << input << endl;