CODEWITHSUNDEEP
c++fileifstream
ebdecastro
ebdecastro

Reputation: 71

How to read only numbers in file .txt?

I need to read only numbers from a file. The file contains:

0
#####################
#    |    |    |    #
#    |    |    |   2#
#    |    |   2|    #
#    |    |    |    #
#####################

I only want to read the first 0 that will be the score and the other two numbers. Whitespaces I want to save them as 0. I want to save the score into an int and the rest into a vector.

So the vector should contain:

score = 0
0000000200200000

My code is the next, but it doesn't work:

string line;
vector<int> v;
int sscore = 0, count = 0;
ifstream in ("save_game.txt");
vector<vector<Tile> > vt;

if (in.is_open()) {

    while (getline (in, line)) {
        if (line.size() == 1)
            sscore = str2int(line);
        else {
            for (int i = 0; i < (int) line.size(); i++) {
                string l = line.substr(i, 1);
                char c = l[0];
                if (l[0] == '#' || l[0] == '|') {count = 0;}
                else {
                    if (c != ' ') {
                        count = 0;
                        int ss = str2int(l);
                        v.push_back(ss);
                    }
                    else {
                        count++;
                        if (count == 3)
                            v.push_back(0); 
                    }
                }
            }
        }
    }

    in.close();
}

And here is the str2int function

int str2int(string s){
    istringstream reader(s);
    unsigned int val = 0;
    reader >> val;
    return val;
}

Thank you very much.

Upvotes: 0

Views: 1611

Answers (2)

AldiT
AldiT

Reputation: 126

Just ignore the other input and save what is a digit , check what i did it worked for the same text file you posted, in the end the vector must have 0 2 2 as values. screenshot

I forgot to make 0 all the other characters but that isn't an issue now just replace continue; statement in the screen shot with nums.push_back(0);

Upvotes: 0

LogicStuff
LogicStuff

Reputation: 19607

I would use only simple stream extraction operations here (actually, maybe boost::regex_split), no std::string parsing.

  • Read the first 0 with operator>>, then std::ignore to remove the trailing newline character, or std::getline and check if no extra (non-whitespace) characters are present

  • std::ignore or std::getline and validate the #### lines.

  • Use operator>> with a char and validate that it is #.

  • In a loop, try operator>> with int defaulted to 0, if it fails, in.clear() and use operator>> with a char to read what doesn't seem to be a number, but either | or #. Continue the loop according to that.

  • Handle the rest of the line after the second # similarly to the 1st bullet point

Always check if every extraction operation succeeded.

Upvotes: 1

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