README.md

Chapter 1 Tutorial

This chapter is a tour of the basic components of Go.

Content

1. Hello, World
2. Command-Line Arguments
   1. Modify the echo program to also print os.Args[0], the name of the command that invoked it.
   2. Modify the echo program to print the index and value of each of its arguments, on per line.
   3. Experiment to measure the difference in running time between out potentially inefficient versions and the on that uses strings.Join

Highlights

Semicolons

Newlines following certain tokens are converted into semicolons, so where newlines are placed matters to proper parsing of Go code. For instance, the poening brace { of the function must be on the same line as the end of the func declaration, ont on a line by itself, and in the expression x+y, a newline is permitted after but not before the + operator.

Assignment Operator

s += sep + os.Args[i]

The statement is an assignment operator; it is equivalent to

s = s + sep + os.Args[i]

The operator += is an assignment operator. Each arithmetic and logical operator like + or * has a corresponding assignment operator.

Iteration of map

The order of map iteration is not specified, but in practice it is random, varying from one run to another. This design is intentional, since it prevents programs from relying on any particular ordering where none is guaranteed.

bufio Package

It helps make input and output efficient and convenient. One of its most useful features is called Scanner that reads input and breaks into lines or words; it's often the easiest way to process input that comes naturally in lines.