课堂作业01

课堂作业练习题

1.显示三条信息

package Ch01;

public class Ex01_01 {
    public static void main (String [] args){
        System.out.println("Welcome to Java");
        System.out.println("Welcome to Computer Science");
        System.out.println("Programming is fun");

    }
}

2.显示五条信息Welcome to java

package Ch01;

public class EX01_02 {
    public static void main (String [] args){
        System.out.println("Welcome to java");
        System.out.println("Welcome to java");
        System.out.println("Welcome to java");
        System.out.println("Welcome to java");
        System.out.println("Welcome to java");

    }
}

3.编写java图案

package Ch01;

public class Ex01_03 {
    public static void main (String []args){
        System.out.println("     J     A     V     V     A");
        System.out.println("     J    A A     V   V     A A");
        System.out.println("  J  J   AAAAA     V V     AAAAA");
        System.out.println("   JJ   A     A     V     A     A");

    }

}

4.打印表格

package Ch01;

public class Ex01_04 {
    public static void main(String [] args)
    {
        System.out.println("a     a^2     a^3");
        System.out.println("1     1       1");
        System.out.println("2     4       8");
        System.out.println("3     9       27");
        System.out.println("4     16      64");

    }
}

5.编写程序表示（计算表达式），显示以下式子的结果

public class Ex01_05 {
    public static void main (String []args)
    {
        double a;
                double b;
                        double c;
                                double d;
                                        //Declare a b c d为实数，也称浮点数）
        a = 9.5; b = 4.5; c = 2.5; d = 3.5;
        double outcome1; double outcome2; double outcome;
                outcome1 = a * b - c * 3;
            outcome2 = 45.5 - d;
            outcome = outcome1/outcome2;
            System.out.println("The answer is" + outcome);
            /*其实没有必要赋值a，b，c，d可直接通过outcome1=9.5*4.5-2.5*3...实现
            但是想练习用double表明浮点数以及记住每个命令后都需要；结尾，因此选择这样多练习了几次
            应该算是有损计算机性能的方法，不过不管怎么说都出结果了
             */

    }
}

计算归计算，结果还是需要用System.out.println("")表示出，才会在控制台中显示*

6.编写程序数列求和

package Ch01;

public class Ex01_06 {
    public static void main(String[] args) {
        double outcome ;
        outcome= 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9;
                System.out.println("The answer is " + outcome);
    }
}