Using getline to extract information and store them in a datatype in c++

Here's a code that I wrote which isn't comple开发者_如何学编程te.

string line; 
ifstream fp ("foo.txt"); 
if (fp.fail()){
    printf("Error opening file %s\n", "foo.txt");
    return EXIT_FAILURE; 
}

unsigned int lineCounter(1); 
while(getline(fp, line)){
    if(lineCounter == 1){
        lineCounter++;
    } // to skip first line
    else{
        // find and extract numbers
    } 
}

The foo.txt file looks like this.

x0,x1,y0,y1
142,310,0,959
299,467,0,959
456,639,0,959
628,796,0,959

Basically, numbers are x and y coordinates.All I need is to extract the numbers in a datatype that is easy to read and be able to access them like a matrix. It should store as 4 containers, having [142, 310, 0, 959], [299, 467, 0, 959]...and so on for the 4 lines.

I tried find() function, but I'm not sure how to use that correctly to put them in the datatype.

How do I extract only the numbers and store them in a datatype that I can move around in and access them like arrays?

---

To read 4 numbers seporated by comma do this;

std::string line;
std::getline(file, line);

std::stringstream linestream(line);

int  a,b,c,d;
char sep; // For the comma

// This should work even if there are spaces in the file.
// The operator >> will drop leading white space
// Then read the next type
//      For int object will read an integer from the stream
//      For char object will read the next char (after dropping leading white space)
linestream >> a >> sep >> b >> sep >> c >> sep >> d;

---

Building on @Martin's answer:

std::string line;
std::getline(file, line);

std::stringstream linestream(line);

int  a,b,c,d;
char sep; // For the comma

// This should work even if there are spaces in the file.
// The operator >> will drop leading white space
// Then read the next type
//      For int object will read an integer from the stream
//      For char object will read the next char (after dropping leading white space)
linestream >> a >> sep >> b >> sep >> c >> sep >> d;

How do we get these four values into a matrix-like data structure? First, declare this somewhere with appropriate scope & lifetime:

std::vector< std::vector<int> > matrix; // to hold everything.

Next, add this code to your line-reading loop:

{
    std::vector <int> vi;
    vi.push_back(a);
    vi.push_back(b);
    vi.push_back(c);
    vi.push_back(d);
    matrix.push_back(vi);
}

Finally, in your code that analyzes the matrix:

int item;
item = matrix[0][0] + matrix[1][1] + matrix[2][2]; // for example.