第十单元(语言结构)
<h1>语言结构</h1>
<ul>
<li>
<p>顺序结构:程序自上而下执行,无分支无循环</p>
</li>
<li>
<p>选择结构:根据不同条件执行不同动作</p>
</li>
<li>循环结构:当指定的条件为真时循环执行代码块</li>
</ul>
<h2>一、分支结构</h2>
<blockquote>
<p>条件语句需要开发者通过指定一个或多个条件,并通过测试条件是否为 true 来决定是否执行指定语句,
并在条件为 false 的情况在执行另外的语句。</p>
</blockquote>
<pre><code class="language-go">package main
import "fmt"
func main() {
/* 定义局部变量 */
var a int = 10
/* 使用 if 语句判断布尔表达式 */
if a < 20 {
/* 如果条件为 true 则执行以下语句 */
fmt.Printf("a 小于 20\n" )
}
fmt.Printf("a 的值为 : %d\n", a)
}</code></pre>
<pre><code class="language-go">
package main
import "fmt"
func main(){
var grade string = "B"
var marks int = 10
switch marks{
case 90: grade = "A"
case 80: grade = "B"
case 70: grade = "C"
case 60: grade = "D"
default:grade = "E"
}
switch{
case grade == "A":
fmt.Println("优秀")
case grade == "B":
fmt.Println("良好")
case grade == "C":
fmt.Println("及格")
case grade == "D":
fmt.Println("不及格")
default:
fmt.Println("差")
}
}
</code></pre>
<h2>二、循环结构</h2>
<pre><code class="language-go">package main
import "fmt"
func main() {
age := 20
if age > 18 {
fmt.Println("可以去网吧冲浪")
}else{
fmt.Println("小学生回家写作业吧")
}
}
</code></pre>
<pre><code class="language-go"> /*
sum:= 0
for i:=1;i<=100;i++{
sum += i;
}
fmt.Printf("1-100之间的和为%d",sum);
*/
/*
sum:= 0
for i:=1;i<=100;i++{
if i%2 == 0 {
sum += i
}
}
fmt.Printf("1-100之间所有偶数的和为%d",sum);
*/
//9 9 乘法表
/*
for i:=1;i<=9;i++{
for j:=1;j<=i;j++{
fmt.Printf("%d*%d=%d\t",i,j,i*j)
}
fmt.Println()
}
*/</code></pre>
<h2>循环案例</h2>
<pre><code class="language-go">
/*
for k,v := range[] int {1,2,3,4}{
fmt.Printf("key:%d value:%d ",k,v);
fmt.Println()
}
*/
/*
car := [...]string{"BMW","Benz","Audi","Volvo"}
for i :=0 ;i< len(car);i++ {
fmt.Println(car[i]);
}
*/
/*
city:= [...]string{"北京", "上海", "深圳","洛阳"}
for k,v := range city {
fmt.Printf("key:%d value:%s ",k,v)
fmt.Println()
}
*/
/*
students := make(map[string]string)
students["name"] = "张三"
students["sex"] = "男"
fmt.Println(students)
*/
/*
var citys map[string]string
citys = make(map[string]string)
citys["China"] = "北京"
citys["France"] = "巴黎"
citys["Italy"] = "意大利"
citys["Japan"] = "东京"
for k,v := range citys{
fmt.Println(k,v)
}
*/
/*
goods := [3][3]string{
{"北京","上海","广州"},
{"深圳","重庆","成都"},
{"洛阳","淄博","三亚"},
}
fmt.Println(goods);
*/</code></pre>