Question

Good morning to everybody, 🙂

I have writen a code in C++ that reads information from a txt file. It takes the information in the first row saving it in a string and then I want to work with this info. I want to read this string and when it finds a “|” character it must jump to a new line. Its something quite easy but I’m having problems when executing and I’ve been trying to find the problem for hours and I haven’t suceed. 🙁 I attached the code.

Thanks in advance for your help.

#include <string>
#include <fstream>
#include <vector>
#include <iostream>

using namespace std;

int main()
{

    ifstream ifs( "C:\\a\\text.txt" );
    string temp;

    getline( ifs, temp ); 
    cout<<temp<<endl;

    string * pch;
    pch = strtok (temp,"|");

    while (pch != NULL)
    {
        printf ("%s\n",pch);
        pch = strtok (NULL, "|");
    }

    system("pause");
    return 0;

}

Answer 1

strtok works with char*, not string*. That’s probably why you’re experiencing issues.

Since you’re implementing this with c++, I suggest you use the string functions instead of strtok:

int main()
{

    ifstream ifs( "C:\\a\\text.txt" );
    string temp;

    getline( ifs, temp ); 
    cout<<temp<<endl;

    size_t tokenPos = temp.find("|");   

    while (tokenPos != string::npos)
    {
        cout << temp.substr(0, tokenPos) << endl;
        temp.erase(0, tokenPos+1);
        tokenPos = temp.find("|");  
    }

    system("pause");
    return 0;

}

To store your text in the values you described in your comment, you’d do the following:

int main() 
{ 
    ifstream ifs( "C:\\a\\text.txt" ); 

    int id; 
    int type; 
    int columns; 
    string temp; 

    getline( ifs, temp ); 
    cout<<temp<<endl; 

    size_t tokenPos = temp.find("|");
    while (tokenPos != string::npos) 
    { 
        int i=0; 
        tokenPos = temp.find("|"); 
        cout << temp.substr(0, tokenPos) << endl; 

        if(i==0)
        { 
            id = atoi(temp.substr(0, tokenPos).c_str()); 
        }
        else if(i==1) 
        { 
            type = atoi(temp.substr(0, tokenPos).c_str()); 
        } 
        else if(i==2) 
        { 
            columns = atoi(temp.substr(0, tokenPos).c_str()); 
        } 

        ++i; 
        temp.erase(0, tokenPos+1); 
    } 

    cout << "ID: " << id << ", Type: " << type << ", Columns: " << columns << endl; 
    system("pause"); 
    return 0; 
}