Why Doesn't My `ifstream.open()` Work with a String in Dev-C ?

Open Function Not Found for ifstream in dev cpp

The provided code attempts to open a file using file.open(name), where name is a string. However, this code compiles successfully in Visual Studio (VS) but not in dev cpp. The error message indicates that there is no matching function for the open method with a string argument.

The root cause of this issue is that the support for using a string argument in the open function was only introduced in C 11. While VS supports C 11, dev cpp appears to be using an older version of the C standard, which does not include this feature.

Solution:

To resolve this issue, there are two approaches:

1. Use c_str(): Convert the string argument to a character array using the c_str() method and pass that array to the open function:

   file.open(name.c_str());

2. Use Constructor: Alternatively, you can use the constructor of ifstream that takes a string argument:

   std::ifstream file(name.c_str());

In addition, to avoid unnecessary copy, it is recommended to pass the string argument to loadNumbersFromFile() by constant reference:

std::vector<int> loadNumbersFromFile(std::string const& name)</int>

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