Develop a hello.go program

package main

import "fmt"

func main() {
    
    
	fmt.Print("hello")
}

输出:
hello

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Explanation of the above figure

The suffix of the go file is .go
package main indicates that the package where the hello.go file is located is main, and in go, each file must belong to a package.
import "fmt" means: import a package, the package name is fmt, after importing the package, you can use the functions of the fmt package
- For example: fmt.Println
func main() { }
- func is a keyword indicating a function.
- main is the function name, which is a main function, which is the entry point of our program.
fmt.Println("hello") means calling the function Println of the fmt package to output hello, world

Golang execution process analysis

If the source code is compiled and then executed, the execution flow of Go is as follows
If we directly execute the go run source code on the source code, the execution flow of Go is as follows

If we first compile and generate an executable file, then we can copy the executable file to a machine without a go development environment, and it can still run
If we directly go run the go source code, then if we want to run it on another machine, we also need a go development environment, otherwise it cannot be executed.
When compiling, the compiler will include the library files that the program depends on in the executable file, so the executable file becomes much larger.

With the go source file, compile it into a binary code file that the machine can recognize through the compiler.
In the source file directory, compile the hello.go file through go build. The generated executable file name can be specified
It must be .exe suffix under windows, and an executable file under Linux
If there is an error in the program, an error will be reported on the wrong line when compiling. Helps programmers debug errors

Go source files have a "go" extension.
The execution entry point of a Go application is the main() function.
The Go language is strictly case-sensitive.
A Go method is composed of one statement after another, and no semicolon is required after each statement (Go language will automatically add a semicolon after each line)
The Go compiler compiles line by line, so we write one statement per line, and we cannot write multiple statements in the same line, otherwise an error will be reported
If the variables defined by the Go language or the imported packages are not used, the code cannot be compiled.
- Use the goland development tool, if it is not applicable, it will be automatically deleted
If the variables defined by the go language or the imported packages are not used, the code cannot be compiled
Curly braces appear in pairs and are indispensable.

The text used to annotate and explain the program is a comment, which improves the readability of the code;
Comments are a good programming habit that a programmer must have.
Sort out your own thoughts through comments first, and then use code to reflect them.

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