lst-0010-book.cpp
// https://godbolt.org/z/ssW3eKEGq
#include <iostream> // cerr
#include <fstream>
int main(int argc, char* argv[]) {
int value;
std::ifstream myInput{"input1.txt"};
if(!myInput) {
std::cerr << "Error opening file!\n";
} else {
myInput >> value;
}
}