Reading from a file

I wanted to know if it's possible to somehow determine if the line ends if im using something like fin >> something? Like in the code bellow, if the input file is ok, then everything is fine. But if somethings missing, it goes down. Like usualy it reads 3 variables from each line. But if there's variable missing in the line, i should know that. So i can read 3 variables from the next line etc. I dont really want to read symbol by symbol.

int main()
{
    int ministrijas = 0;// Amount of roots
    int Knot = 0;// Children ID
    int Budget = 0; // children value
    int Ministry = 0;// root ID
    int Parent = 0;// Parent of the children
    ifstream fin;
    ofstream fout;
    List h;
    fin.open("budget.i1");
    fout.open("budget.o1");
    fin >> ministrijas;
    for(int i=0; i < ministrijas; i++)
    {
        fin >> Knot >> Budget;
        h.AddKnot(Ministry, Knot, Budget );
    }
    while(fin>>Parent>>Knot>>Budget)
    {
        h.AddKnot(Parent, Knot, Budget);
        h.LinkKnots(Parent, Knot);

    }

The input file looks like this:

1 //Defines the amount of roots
1 150 // Adds Root
1 11 30 // Then adds children to the root. 1 stands for the root ID, 11 is the id of the Children. 30 is the value of the children.
1 12 120
1 12 // Like here. The children is missing a value. Here's the problem.
11 111 10
11 112 20

mpark4656 (181)

Something like this?

#include <fstream>
#include <sstream>
#include <iostream>
#include <string>

int main()
{
    std::ifstream inFile ( "test.txt" );

    std::string line;   // Stores each line from the txt file

    std::istringstream iss;

    int ministrijas , knot , budget , parent;


    inFile >> ministrijas >> knot >> budget;    // Read the first 2 lines from the file

    std::cout << ministrijas << std::endl << knot << ' ' << budget << std::endl;



    std::getline ( inFile , line );     // Store a line from the file in the string variable, line

    // As long as a line can be read from the file
    while ( std::getline ( inFile , line ) ) {

        iss.str ( line );   // Set line as the content of iss

        // If 3 variables can be read from iss
        if ( iss >> parent >> knot >> budget )
            std::cout << parent << ' ' << knot << ' ' << budget << std::endl;
        else {
            std::cout << "Less than 3 Variables on this Line ..." << std::endl;

            iss.clear ();       // Reset the bit of iss
        }
    }

    return 0;
}

test.txt

Output

1
1 150
1 11 30
1 12 120
Less than 3 Variables on this Line ...
11 111 10
11 112 2

Process returned 0 (0x0)   execution time : 0.016 s
Press any key to continue.

After the second line, the program starts reading line by line and store each line in iss. If the program cannot read 3 items from the iss, it prints "Less than 3 Variables on this Line ..." and continues on to the next line.

Is this what you were looking for?

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Reading from a file