C++ 'getline' No instance of overloaded function matches argument list

Question

Trying to use getline but the error keeps saying: No instance of overloaded function matches argument list.

 #include <iomanip>
 #include <string>
 #include <iostream>
 #include <fstream>
 #include <iomanip>

using namespace std;
int main()
{
    int lengthInput;
    int widthInput;
    ifstream fileOpening;
    fileOpening.open("testFile.txt");

while (!fileOpening.eof())
    {
//ERROR ON NEXT TWO LINES OF CODE**
        getline(fileOpening, lengthInput, ' ');
        getline(fileOpening, widthInput, ' ');
    }

    system("pause");
    return 0;

which of the overloads listed [here](https://en.cppreference.com/w/cpp/string/basic_string/getline) are you trying to call? — 463035818_is_not_an_ai, Oct 14 '19 at 21:27
Also, [Why is iostream::eof inside a loop condition (i.e. `while (!stream.eof())`) considered wrong?](https://stackoverflow.com/questions/5605125/) — Remy Lebeau, Oct 14 '19 at 21:29
What does your file actually look like? Are you actually trying to read integers, or strings? — Remy Lebeau, Oct 14 '19 at 21:32

score 1 · Answer 1 · answered Oct 14 '19 at 21:28

1

The 2nd parameter of std::getline() expects a std::string to write to, but in both cases you are passing in an int instead. That is why you are getting the error - there really is no version of std::getline() that matches your code.

answered Oct 14 '19 at 21:28

Remy Lebeau

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score 1 · Answer 2 · edited Jun 20 '20 at 09:12

The second argument of getline is expected to be a reference to a std::string, not a reference to an int.

If you expect that the pair of values can be read from multiple lines, you can use:

while (fileOpening >>  lengthInput >>   widthInput)
{
   // Got the input. Use them.
}

If you expect that the pair of values must be read from each line, you'll have to use a different strategy.

Read lines of text.
Process each line.

std::string line;
while ( fileOpening >> line )
{
   std::istringstream str(line);
   if (str >>  lengthInput >>   widthInput)
   {
      // Got the input. Use them.
   }
}

Important Note

Don't use

while (!fileOpening.eof()) { ... }

See Why is iostream::eof inside a loop condition (i.e. `while (!stream.eof())`) considered wrong?.

C++ 'getline' No instance of overloaded function matches argument list

2 Answers2

Important Note