[Java知识库]日撸代码300行学习笔记 Day 4

1.Day 4：实现闰年的计算

?在闵老师的代码中，不难发现在其中一部分if语句中，嵌套了定义的boolean类型的isLeapYear以及isLeapYearV2函数，对其进行调用。在第一种函数中，采用逻辑运算符 && 和 || 在进行判别，返回true或false。第二种是采用if语句进行计算判别。并且在输出时，换成了print，可以使先后不同的输出语句在同一排显示，如果需要提行，则换成了println。

package demo;

public class Demo1 {
	public static void main(String[] args) {

		// Test isLeapYear
				int tempYear = 2021;

				System.out.print("" + tempYear + " is ");
				if (!isLeapYear(tempYear)) {
					System.out.print("NOT ");
				} // Of if
				System.out.println("a leap year.");

				tempYear = 2000;

				System.out.print("" + tempYear + " is ");
				if (!isLeapYear(tempYear)) {
					System.out.print("NOT ");
				} // Of if
				System.out.println("a leap year.");

				tempYear = 2100;

				System.out.print("" + tempYear + " is ");
				if (!isLeapYear(tempYear)) {
					System.out.print("NOT ");
				} // Of if
				System.out.println("a leap year.");

				tempYear = 2004;

				System.out.print("" + tempYear + " is ");
				if (!isLeapYear(tempYear)) {
					System.out.print("NOT ");
				} // Of if
				System.out.println("a leap year.");

				// Test isLeapYearV2
				System.out.println("Now use the second version.");
				tempYear = 2023;

				System.out.print("" + tempYear + " is ");
				if (!isLeapYearV2(tempYear)) {
					System.out.print("NOT ");
				} // Of if
				System.out.println("a leap year.");

				tempYear = 2006;

				System.out.print("" + tempYear + " is ");
				if (!isLeapYearV2(tempYear)) {
					System.out.print("NOT ");
				} // Of if
				System.out.println("a leap year.");

				tempYear = 2105;

				System.out.print("" + tempYear + " is ");
				if (!isLeapYearV2(tempYear)) {
					System.out.print("NOT ");
				} // Of if
				System.out.println("a leap year.");

				tempYear = 2004;

				System.out.print("" + tempYear + " is ");
				if (!isLeapYearV2(tempYear)) {
					System.out.print("NOT ");
				} // Of if
				System.out.println("a leap year.");
			}// Of main	
			public static boolean isLeapYear(int paraYear) {
				if ((paraYear % 4 == 0) && (paraYear % 100 != 0) || (paraYear % 400 == 0)) {
					return true;
				} else {
					return false;
				} // Of if
			}// Of isLeapYear

			public static boolean isLeapYearV2(int paraYear) {
				if (paraYear % 4 != 0) {
					return false;
				} else if (paraYear % 400 == 0) {
					return true;
				} else if (paraYear % 100 == 0) {
					return false;
				} else {
					return true;
				} // Of if
			}// Of isLeapYearV2
}

Part 1结果：

?Part 2结果：

?2.Question

在赋值中，例如? int num=1和 int num = 1中，等号两边加不加空格好像都不影响程序的运行，那我们平常在写的时候，是否是要加上这种空格喃？