Notes on the swift programming language-page 24th

The swift Programming Language Reading Notes on the seventh page contains two main content: print the output and how to comment out code 1 in swift how to print the value of variables and constants? Use the println function. For details, the println function outputs a line feed in addition to the variable constant value. 1) print the constant eg1 let hW = "Hello chinagame. me "println (HW) => The String constant can be output to the console. 2) print the variable and use \ (variable name) to output it in double quotation marks, this is like % s eg2 var QQ = 1941847311 println ("My QQ's number is \ (qq)") in C language. How can I comment out the code? 1) Use // to comment out a single line of code. 2) Use/* and */to comment multiple lines in the same way as other languages.