Java，使用多个条件语句的问题，while循环，for loop，if语句

int x = 10;
if (x > 0) {
    System.out.println("x是正数");
} else if (x < 0) {
    System.out.println("x是负数");
} else {
    System.out.println("x是零");
}

int dayOfWeek = 3;
switch (dayOfWeek) {
    case 1:
        System.out.println("星期一");
        break;
    case 2:
        System.out.println("星期二");
        break;
    case 3:
        System.out.println("星期三");
        break;
    default:
        System.out.println("其他");
}

int count = 0;
while (count < 5) {
    System.out.println("count的值为：" + count);
    count++;
}

for (int i = 0; i < 5; i++) {
    System.out.println("i的值为：" + i);
}

int num = 10;
if (num > 0) {
    System.out.println("num是正数");
}