package main

import "fmt"

/*
	for循环：某些代码会多次的执行
*/
func main() {
	for i := 1; i <= 3; i++ {
		fmt.Println(i, "hello world")
	}

	//省略1，3表达式，只保留2表达式。相当于while条件
	j := 1
	for j <= 5 {
		fmt.Println(j)
		j++
	}

	//同时省略三个表达式，相当于while true，死循环
	// for {
	// 	fmt.Println(j)
	// 	j++
	// }

	//嵌套循环
	for m := 0; m < 5; m++ {
		for n := 0; n < 5; n++ {
			fmt.Print("*")
		}
		fmt.Println()
	}

	//break和continue
	for x := 1; x < 8; x++ {
		if x == 5 {
			break
		}
		fmt.Println(x)
	}
	fmt.Println("==================")
	for x := 1; x < 8; x++ {
		if x == 3 || x == 5 {
			continue
		}
		fmt.Println(x)
	}
	fmt.Println("==================")

	//嵌套循环，在内层break/continue外层循环
out: //外层循环命名
	for m := 0; m < 5; m++ {
		for n := 0; n < 5; n++ {
			fmt.Print("*")
			if n == 1 {
				break out
			}
		}
		fmt.Println()
	}

}

执行结果

1 hello world
2 hello world
3 hello world
1
2
3
4
5
*****
*****
*****
*****
*****
1
2
3
4
==================
1
2
4
6
7
==================
**