【Java】第2章 上机实践与习题

实验1 联合编译

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代码

如下

MainClass .java

package Test1_JointCompilation;

public class MainClass {
    public static void main(String args[]) {
        System.out.println("你好，只需编译我");
        A a = new A();
        a.fA();
        B b = new B();
        b.fB();
    }
}

A.java

package Test1_JointCompilation;

public class A {
    void fA() {
        System.out.println("I am A");
    }
}

B.java

package Test1_JointCompilation;

public class B {
    void fB() {
        System.out.println("I am B");
    }
}

C.java

package Test1_JointCompilation;

public class C {
    void fC() {
        System.out.println("I am C");
    }
}

运行结果

如下

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实验2 希腊字母表

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代码

如下

GreekAlphabet .java

package Test2_GreekAlphabet;

public class GreekAlphabet {
    public static void main(String args[]) {
        int startPosition = 0, endPosition = 0;
        char cStart = 'α',cEnd = 'ω';
        startPosition = (int)cStart;		//将cStart做int型转换运算，并将结果赋值给startPosition
        endPosition = (int)cEnd;
        System.out.println("希腊字母\'α\'在unicode表中的顺序位置: " + startPosition);
        System.out.println("希腊字母表:");
        for(int i = startPosition; i <= endPosition; i++) {
            char c = '\0';
            c = (char)i;
            System.out.print(" " + c);
            if((i - startPosition + 1) % 10 == 0)   //每 10 个换行
                System.out.println("");
        }
    }
}

运行结果

如下

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实验3 键盘输入数据

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代码

如下

InputData .java

package Test3_EnterDataFromTheKeyboard;

import java.util.Scanner;

public class InputData {
    public static void main(String args[]) {
        Scanner inTo = new Scanner(System.in);
        int amount = 0;
        float price = 0, sum = 0;
        System.out.println("输入产品数量(回车确认)：");
        amount = inTo.nextInt();
        System.out.println("输入产品单价(回车确认)：");
        price = inTo.nextFloat();
        sum = amount * price;
        System.out.printf("数量:%d, 单价:%5.2f, 总价值:%5.2f", amount, price, sum);

    }
}

运行结果

如下

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习题2

习题

1.BD
2.代码123
3.前者常量需加后缀F
4.----在下面
5.链接： 习题4.5.代码.