Finding the string of number present inside brakects after a keywrod in a file

I am reading a file whick looks like following:

Code:

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10 = NAND(1, 3)
11 = NAND(3, 6, 5)
15 = NAND(9, 6, 2, 8)

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Problem: I have to find the word "NAND" and then find the numbers inside the brackets because they are the inputs to that NAND gate. I have written a code below but that code can detect the fixed number of inputs. I need a code which can detect any number of inputs (whether 2 inputs or more than two). But i don't understand how do i do that?

My code:

Code:

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        string input_str ("INPUT"), output_str ("OUTPUT"), nand_str("NAND");
       
    while (getline( input_file, line )) 
        {
                std::size_t guard_found = line.find(guard_str);
                if (guard_found ==std::string::npos)
                {
                        ///NAND
                        std::size_t found_2 = line.find(nand_str);
                        if (found_2!=std::string::npos)
                        {
                                vector <string> nand_inputs;
                               
                                found_2 = line.find_first_of('(', found_2 + 1);
                                //find first input
                                string first_input = line.substr( found_2 + 1, ( line.find_first_of(',', found_2) - found_2 - 1) );
                                nand_inputs.push_back(first_input);
                                //Second input
                                found_2 = line.find_first_of(',', found_2 + 2);
                                string second_input = line.substr( found_2 + 2, ( line.find_first_of(')', found_2) - found_2 - 2) ); //CHANGED "found_2 + 1"  TO "found_2 + 2" AND "found_2 - 1" TO "found_2 - 2"
                                nand_inputs.push_back(second_input);
                                                               
                                cout<<"first: "<<first_input;
                        }                       


                }
}

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This code snippet should give you help with the way forward,

Code:

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const string nand_str = "NAND(";
const string nline = "15 = NAND(9, 6, 2, 8, 10, 23)";

size_t        nand,
        del;

        if ((nand = nline.find(nand_str)) != string::npos)
                nand += nand_str.length();

        for (; nand != string::npos; nand = del)
                if ((del = nline.find_first_of(",)", nand)) != string::npos)
                        cout << atoi((nline.substr(nand, del++ - nand)).c_str()) << endl;

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PS Why are you saving the nand inputs as a vector<string>? Why not save them as a vector<int>?
ie

Code:

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vector<int> nand_inputs;
....
nand_inputs.push_back(atoi((nline.substr(nand, del++ - nand)).c_str()));

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Thanks alot. It did work for me BUT it is printing an extra space i.e. " " for the inputs which are between 1st and last input. For example, the inputs which i am getting for Second line of my text file are "3", " 6", " 5". See, there is an extra space before 6 and 5 which should not be present. I can try to remove this space by making an "if condition" and getting an another string. But is there any good and short solution for it?

PS: I am not converting the string into number because my i have to process the input names as string only in my further code.

Quote:

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BUT it is printing an extra space i.e. " " for the inputs which are between 1st and last input

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Coverting to a number doesn't have this issue :D I'll have a look and get back.

Thank you. But i need it into string format only :)

Assuming there is only one space after the , then possibly the simplest way is

Code:

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const string nand_str = "NAND(";
const string nline = "15 = NAND(9, 6, 2, 8, 10, 23)";

size_t        nand,
        del;

        if ((nand = nline.find(nand_str)) != string::npos)
                nand += nand_str.length() - 1;

        for (; nand != string::npos; nand = del)
                if ((del = nline.find_first_of(",)", nand)) != string::npos)
                        cout << nline.substr(nand + 1, del++ - nand - 1) << endl;

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Note that if there are more than 1 space after the , then this simple solution won't work.

Thanks a lot. But i am using your previous technique through which i get the input in "integer" form and then i convert it into "string". Using that way also, i am able to remove and extra whitespace. This strategy is also ok?

Yes - it just makes the process slightly slower.

This will give you the numbers as a string without the leading space(s) and without the overhead of all the copying from converting to/from an integer irrespective of how many spaces there are between them.

Code:

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const string nand_str = "NAND(";
const string nline = "15 = NAND(    9,6,    2, 8,    10,23  )";

size_t        nand,
        del;

        if ((nand = nline.find(nand_str)) != string::npos)
                nand += nand_str.length();

        for (nand = nline.find_first_not_of(" ", nand); nand != string::npos; nand = nline.find_first_not_of(" ", del))
                if ((del = nline.find_first_of(",)", nand)) != string::npos)
                        cout << nline.substr(nand, del++ - nand) << endl;

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