Java Flow Control Statement 流程控制语句

Java Flow Control Statement 流程控制语句

用来控制程序的执行流程

Loop differentiation 循环区别 

for	如果已知循环多少次使用for，控制循环只能在循环中{}中使用，先判断后执行
while	如不清楚执行多少循环使用while，控制循环后还可以使用，先判断后执行
do_while	首次执行后判断

Jump loop statement 跳转循环语句

break	用于结束当前循环语句或结束所在switch分支执行
continue	用于跳出当前循环进入下一个循环程序

sequence 顺序结构

默认程序执行顺序

Branch structure 分支结构

If.case

Scanner sc =  new Scanner(System.in);
int heartbeat = sc.nextInt();
if (heartbeat < 60 || heartbeat > 100) {
         System.out.println(("您的心跳数据是：" + heartbeat + "您需要进一步检查"));
        }
        System.out.println(("检查结果" + heartbeat + "您的身体ok"));

Scanner sc = new Scanner(System.in);
System.out.println(("请输入红包金额:"));
double money = sc.nextDouble();
double money_one = 1000;
if (money_one >= money) {
         System.out.println(("发送成功"));
}else {
         System.out.println(("no"));
}

Scanner sc = new Scanner(System.in);
System.out.println("请数");
int jx = sc.nextInt();
if (jx >= 0 && jx < 60) {
       System.out.println(("C:1000"));
} else if (jx >= 60 && jx < 80) {
       System.out.println(("B:2000"));
} else if (jx >= 80 && jx <= 100) {
       System.out.println("A:3000");
} else {
       System.out.println("最高100");
}

switch.case

适合做值匹配选择结构格式清晰

Scanner sc = new Scanner(System.in);
System.out.println(("请输入："));
String Phone = sc.next();
switch (Phone) {
   case "苹果":
       System.out.println(("IPhone" + "12ProMax" + "256G"));
   break;
   case "华为":
       System.out.println(("HuaWei" + "40" + "256G"));
   case "小米":
       System.out.println(("XIAOMi" + "20" + "64G"));
   default:
       System.out.println(("无数据"));
}

Loop Structure 循环结构

for.case

Scanner sc =new Scanner(System.in);
System.out.println(("请输入："));
String HelloWorld_tect  = sc.next();
for (int i = 0; i < 3; i++){
    System.out.println((HelloWorld_tect));
}

while.case

int i = 0;
while (i < 3) {
     System.out.println(("he"));
     i++;
}

        Scanner sc = new Scanner(System.in);
        System.out.println(("INPUT1"));
        double w = sc.nextDouble();
        double D = 8848860; 
        int counter = 0; 
        while (w < D){
            w *= 2;
            counter++;
        }
        System.out.println("INPUT " + counter);
        System.out.println(("" + w));

do-while.case

        Scanner sc = new Scanner(System.in);
        System.out.println(("INPUT1"));
        double w = sc.nextDouble();
        int conter = 0;
        do {
            System.out.println(w);
            w++;
            conter++;
        } while (w < 20);
        {

        }
        System.out.println("???" + (conter));

 endless loop case 死循环案例

Scanner sc = new Scanner(System.in);
int UserPassword = 520;
while (true) {
System.out.println(("INPUT USER PASSWORD"));
int Password = sc.nextInt();
if (Password == UserPassword) {
System.out.println(("CORRect"));
break;
} else {
System.out.println(("Password error INPUT"));
}

nesting loop case 嵌套循环

 for (int i = 0; i <= 5; i++) {
     for (int j = 0; j <= 3; j++) {
          System.out.println(("A"));
            }
            System.out.println(("---------"));

 for (int i = 0; i <= 4; i++) {
     for (int j = 0; j <= 5; j++) {
          System.out.print(("*"));
            }
            System.out.println();

continue case 案例

   for (int i = 1; i <= 5; i++) {
        if (i == 3) {
          continue;
            }
         System.out.println(("INPUT NUMBER" + i));