1. 顺序结构
int a = 18;
if(a < 60){
return 'D';
}else if(a<70){
return 'C';
}else if(a<80){
return 'B';
}else{
return 'A';
}
2. 选择结构
int week = 2;
switch (week){
case 1:
System.out.println("Monday");
break;
case 2:
System.out.println("Tuesday");
break;
case 3:
System.out.println("Wendesday");
break;
default:
System.out.println("sorry, i dont know");
}
3. 循环结构
int a = 0;
while (a < 0){
System.out.println(a);
a++;
}
System.out.println("-----------");
//while和do-while的区别是do-while会保证循环体至少被执行一次
a=0;
do{
System.out.println(a);
a++;
}while (a < 0);
//for循环
for (a = 0; a < 0; a++){
System.out.println(a);
a++;
}
4. 跳转
//需求1:生成0-100随机数,直到生成88为止,停止循环
int total = 0;
System.out.println("Begin!");
while (true){
total ++;
int i = (int)Math.round(100 * Math.random());
if (i == 88)
break;
}
System.out.println("Game over,used " + total + "times.");
System.out.println("------------");
//需求2:输出100~150之间不能被3整除的数
for (int i = 100; i < 150; i++){
if (i % 3 == 0)
continue;
System.out.println(i);
}
5. 多重循环
outer: for (int i = 101; i < 150; i++){
inner: for (int j = 2; j < i / 2; j++){
if (i % j == 0){
continue inner;
}
System.out.println(i + " " + j);
}