[Java基础] 流程控制结构

流程控制结构

1. if - else

     private static String checkHeartBeats(int heatBeats) {
         if (heatBeats > 100) {
             return "too fast";
         } else if (heatBeats >= 60) {
             return "normal";
         } else {
             return "too slow";
         }
     }
   

2. switch - case

       private static String getApha(int month) {
           switch (month) {
               case 1:
                   return "One";
               case 2:
                   return "Two";
               case 3:
                   return "Three";
               case 4:
                   return "Four";
               default:
                   return "Unknown";
           }
       }
   

3. for

       private static void forLoop() {
           for (int i = 0; i < 10; i++) {
               System.out.println(i);
           }
       }
   

4. while

       private static void whileLoop(){
           int i = 1;
           while (i<=10){
               System.out.println(i);
               i++;
           }
       }
   

5. do while

       private static void doWhileLoop() {
           int i = 1;
           do {
               System.out.println(i);
               i++;
           } while (i <= 50);
       }
   

6. 嵌套循环

       private static void mutilLoop() {
           for (int j = 1; j <= 5; j++) {
               for (int i = 1; i <= j; i++) {
                   System.out.print('*');
               }
               System.out.println();
           }
       }
   

7. break - continue

   break：结束当前循环

   continue：跳出当次循环

       private static void breakAndContinue() {
           for (int i = 1; i <= 10; i++) {
               if (i % 3 == 0) {
                   continue;
               }
               if (i % 5 == 0) {
                   break;
               }
               System.out.print(i);
           }
       }
   

8. label 标志 跳出多重循环

       private static void breakAndContinue() {
   
           label:
           for (int j = 1; j <= 4; j++) {
               for (int i = 1; i <= 10; i++) {
                   if (i % 5 == 0) {
                       break label;
                   }
                   System.out.print(i);
               }
               System.out.println();
           }
       }