How to use function freopen_s

Question

In order to read input from a text file, I wrote the following code:

int main(){
    int x;
#ifndef ONLINE_JUDGE
    freopen(\"input.txt\", \"r\", stdin);
#e         


        

Answer 1

I would give you an alternate way. If you still want to use freopen, you can use "-D _CRT_SECURE_NO_WARNINGS" this option with the terminal command, the error message will be suppressed.

In VS you can add it under the following link -

Project-> "Project" Properties -> C/C++ -> Command Line -> Additional Options(Text box on bottom right).

This should resolve the issue!

Answer 2

I would suggest you to avoid using the C style I/O library and use IOSTREAM Library. Its more safe and clean solution. Here is the sample code which opens a file and reads each line into the "std::string" object and prints on the console.

int main() 
{

std::string  file =  "input.txt";
std::string line;
std::ifstream  text_filestream(file.c_str());

while(std::getline(text_filestream, line)) {
 std::cout<<line<<std::endl;
 }
}