Question

I’m trying to read inputs from a file which are marked with {1…9} or X. I need to separate the values and store them in a vector properly. I’m using the “sstringstream” to help me do so:

void myclass::Initialize(ifstream &file_name)
{
    string input;
    int value;
    //Initialize the values in the matrix from the values given
    //in the input file, replace x with a 0
    for(int i = 0; i < 9; i++)
    {
        for(int j = 0; j < 9; j++)
        {   
            //Read the input from the file and determine
            //if the entry is an "int" or "x"
            file_name >> input;
            cout << input << endl;
            istringstream(input); 
            if(input >> value) //PROBLEM HERE!!
            {
                Matrix[i][j] = value;
                cout << "Debug: Check for values in matrix: " << Matrix[i][j] << endl;
            }
            else
                Matrix[i][j] = 0;
        }
    }

    cout << "The values in Matrix after initialization: " << endl;

Print_result();
}

The problem occurs in the if statement, when there is an integer in “input” it doesn’t execute the if statement. I’m not sure why it’s not working.

Answer 1

You’re not actually using the istringstream. I think you’re looking for something like,

..

istringstream is(input); 
if (is >> value)
{

...

Where ‘is’ is the istringstream created from the string “input”.