setw and setfill

setw sets minimum output width
resets to 0 after next output operation
setfill sets the fill characters
Fill character defaults to space
 std::cout  <<  std::setw(10)  <<  123;
 std::cout  <<  std::setw(5) << std::setfill('#');
 std::cout  <<  "hi"  <<  123;
Can also use  std::cout.width(10)
And  std::cout.fill('#')