The type of the expression ‘1’ is char. The type of the expression (test ? 3 : ‘1’) is at least int (or an unsigned version thereof; portably it is std::common_type_t<int, char>). Therefore the two invocations of the << operator select different overloads: The former prints the character as is, the latter formats the integer … Read more
None of the other answers really explain why the compiler generates the code it does in your Godbolt link, so I thought I’d chip in. If you look at the generated code, you can see that: std::cout << ‘\n’; Compiles down to, in effect: const char c=”\n”; std::cout.operator<< (&c, 1); and to make this work, … Read more
Sure, you can (example here): int main() { std::cout << “First message” << std::endl; std::cout.setstate(std::ios_base::failbit); std::cout << “Second message” << std::endl; std::cout.clear(); std::cout << “Last message” << std::endl; return 0; } Outputs: First message Last message This is because putting the stream in fail state will make it silently discard any output, until the failbit … Read more
yes it’s possible to print a string to the console. #include “stdafx.h” #include <string> #include <iostream> using namespace std; int _tmain(int argc, _TCHAR* argv[]) { string strMytestString(“hello world”); cout << strMytestString; return 0; } stdafx.h isn’t pertinent to the solution, everything else is.
You need std::fixed and std::setprecision: std::cout << std::fixed << std::setprecision(3) << a; These require following header: #include <iomanip>
Each has its own overheads. Depending on what you print, either may be faster. Here are two points that come to mind – printf() has to parse the “format” string and act upon it, which adds a cost. cout has a more complex inheritance hierarchy and passes around objects. In practice, the difference shouldn’t matter … Read more
You may not remove last character. But you can get the similar effect by overwriting the last character. For that, you need to move the console cursor backwards by outputting a ‘\b’ (backspace) character like shown below. #include<iostream> using namespace std; int main() { cout<<“Hi”; cout<<‘\b’; //Cursor moves 1 position backwards cout<<” “; //Overwrites letter … Read more
Make sure you flush the stream. This is required because the output streams are buffered and you have no guarantee over when the buffer will be flushed unless you manually flush it yourself. std::cout << “Hello” << std::endl; std::endl will output a newline and flush the stream. Alternatively, std::flush will just do the flush. Flushing … Read more
Generally you use std::cout for normal output, std::cerr for errors, and std::clog for “logging” (which can mean whatever you want it to mean). The major difference is that std::cerr is not buffered like the other two. In relation to the old C stdout and stderr, std::cout corresponds to stdout, while std::cerr and std::clog both corresponds … Read more
std::cout << std::string(100, ‘*’) << std::endl; To move a line up, you have to resort to terminal escapes (assuming that isatty() indicates that you are running on one).