CODEWITHSUNDEEP
c++
jon2512chua
jon2512chua

Reputation: 1062

Why is the extraction operator not working?

I trying out some problems in Google's Code Jam. For the question Store Credit, I have the following code in C++:

    if (input.is_open()) {
    getline(input, line);
    ss << line;
    ss >> nCases;

    for (int i = 0; i < nCases; i++) {
        getline(input, line);
        ss << line;
        ss >> credit;
        cout << credit << endl;

        getline(input, line);
        ss << line;
        ss >> nItems;
        cout << nItems << endl;
        int list[nItems];
    }

input is text file (everything has been correctly initialised), line is a string variable to hold the newly extracted line from the text file, while ss is a stringstream. nCases, credit, and nItems are just int variables. What got me confused is how the extraction operator works as expected when I'm getting nCases but stopped working once I'm trying to retrieve the value for credit and nItems.

Upvotes: 0

Views: 339

Answers (2)

asami
asami

Reputation: 803

if these are just integers per line then why not use atoi

if (input.is_open()) {
    getline(input, line);
    nCases = atoi( line.c_str() );

    for (int i = 0; i < nCases; i++) {
        getline(input, line);
        credit = atoi( line.c_str() );
        cout << credit << endl;

        getline(input, line);
        nItems = atoi( line.c_str() );
        cout << nItems << endl;
        int list[nItems];
    }

Upvotes: 1

Erik
Erik

Reputation: 91270

Instead of ss << line;, reset the stream with ss.str(line); ss.clear();

Upvotes: 3

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