1, 用for循环打印一个4*5的矩形
public class Test {
public static void main(String[] args){
for (int i = 1; i < 5; i++) {
for (int j = 1; j < 6; j++) {
System.out.print("*");//print不换行；
}
System.out.println();//println自动换行；
}
}
}
2, 1-100以内前5个能被3整除的整数
public class Test {
public static void main(String[] args) {
int counter = 0;//counter是计数器
for (int i = 1; i <= 100; i++) {
if (i % 3 == 0) {
System.out.println(i);//能被3整除打印一次记一次
counter++;
}
if (counter == 5) {
break;//记录5次中断循环
}
}
}
}
3, 101-200以内的质数(质数只能被1和自身整除)
public class Test {
public static void main(String[] args) {
for (int i = 101; i <= 200; i++) {
int t = 0;
for (int j = 2; j < i; j++) {
if (i % j == 0) {
t = 1;
break;
}
}
if (t == 0) {
System.out.println(i);
}
}
}
}