第三章 操作符 练习题

Posted 2020-12-26 xiaohai2003ly

/**
 * Created by Sandy.Liu on 2018/7/10.
 */
/**
 * Thinking in java version 4, chapter 3, 3.4
 * Write a program that calculates velocity using a constant distance
 * */
public class Chap3Pra4VelocityCalc {
    static float velocity(float d, float t){
        if(t == 0) return 0f;
        else return d/t;
    }

    }

/**
 * Created by Sandy.Liu on 2018/7/10.
 */
public class Chap3Pra4VelocityCalcTest {
    public static void main(String[] args){
        float d = 300f;
        float t = 2.5f;
        System.out.println("Distance d: "+d);
        System.out.println("Time t: "+t);
        float v = Chap3Pra4VelocityCalc.velocity(d,t);
        System.out.println("Velocity v: "+v);
    }
}

/**
 * Created by Sandy.Liu on 2018/7/10.
 *  Thinking in java version 4, chapter 3, 3.4, practice 5
 *  Create a dog class which includes two string object "name" and "says", create two dog objects
 */
public class Chap3Prac5Dog {
    String name, says;
}

/**
 * Created by Sandy.Liu on 2018/7/10.
 */
public class Chap3Prac5DogTest {
    public static void main(String[] args){
        Chap3Prac5Dog dog1 = new Chap3Prac5Dog();
        Chap3Prac5Dog dog2 = new Chap3Prac5Dog();
        dog1.name = "Spot";
        dog1.says = "Ruff!";
        dog2.name = "Scruff";
        dog2.says = "Wurf!";
        System.out.println("Dog "+dog1.name + " says: "+dog1.says);
        System.out.println("Dog "+dog2.name + " says: "+dog2.says);

    }

}

/**
 * Created by Sandy.Liu on 2018/7/10.
 *  Thinking in java version 4, chapter 3, 3.4, pracetice 6
 *  Create a class called Dog containing two Strings: name and says.
 *  Following exercise 5, create a new God reference and assign it to spot‘s object.
 *  Testing comparison using == and equals() fow all references.
 */
public class Chap3Prac6DogIndex {
    String name;
    String says;
    void setName(String n){
        name = n;
    }
    void setSays(String s){
        says = s;
    }
    void showName(){
        System.out.println(name);
    }
    void showSays(){
        System.out.println(says);
    }
}

/**
 * Created by Sandy.Liu on 2018/7/10.
 */
public class Chap3Prac6DogTest {
    public static void main(String[] args){

        Chap3Prac6DogIndex spot = new Chap3Prac6DogIndex();
        spot.setName("Spot");
        spot.setSays("Ruff!");
        Chap3Prac6DogIndex scruffy = new Chap3Prac6DogIndex();
        scruffy.setName("Scruffy");
        scruffy.setSays("Wurf!");
        spot.showName();
        spot.showSays();
        scruffy.showName();
        scruffy.showSays();

        Chap3Prac6DogIndex butch = new Chap3Prac6DogIndex();
        butch.setName("Butch");
        butch.setSays("hello");
        butch.showName();
        butch.showSays();

        System.out.println("Comparison: ");
        P.print("spot == butch: "+(spot == butch));
        P.print("spot.equals(butch): "+(spot.equals(butch)));
        P.print("butch.equals(spot): " + (butch.equals(spot)));

        P.print("Now assign: butch = spot");
        butch = spot;

        P.print("Compare again: ");
        P.print("spot == butch: "+(spot == butch));
        P.print("spot.equals(butch): "+(spot.equals(butch)));
        P.print("butch.equals(spot): " + (butch.equals(spot)));

        P.print("spot: ");
        spot.showName();
        spot.showSays();

        P.print("butch: ");
        butch.showName();
        butch.showSays();
    }
}

/**
 * Created by Sandy.Liu on 2018/7/11.
 * Write a program that simulates coin-plipping
 */
import java.util.*;
public class Chap3Prac7CoinFlap {
    public static void main(String[] args){
        Random ran = new Random();
        int num1;
        num1 = ran.nextInt(30);
        P.print("num1: "+num1);
        if(num1%2==0) P.print("This is National emblem");
        else P.print("This is heads");

    }
}

/**
 * Created by Sandy.Liu on 2018/7/11.
 * Write a program that simulates coin-plipping
 */
import java.util.*;
public class Chap3Prac7CoinFlap {
    public static void main(String[] args){
        Random ran = new Random();
        int num1;
        num1 = ran.nextInt(30);
        P.print("num1: "+num1);
        if(num1%2==0) P.print("This is National emblem");
        else P.print("This is heads");

    }
}

/**
 * Created by Sandy.Liu on 2018/7/11.
 * thinking in java, version 4, chapter 3, practice 9
 * display the minimum and maximum both for float and double by using e.
 */
public class Chap3Prac9EMeans10 {
    public static void main(String[] args){
        float minf = Float.MIN_VALUE;
        float maxf = Float.MAX_VALUE;

        double mind = Double.MIN_VALUE;
        double maxd = Double.MAX_VALUE;

        P.print("minf: "+minf);
        P.print("maxf: "+maxf);

        P.print("mind: "+mind);
        P.print("maxd: "+maxd);


    }
}

/**
 * Created by Sandy.Liu on 2018/7/11.
 * Write a program with two constant values, one has alternative binary ones and zeros,
 * with a one in the last significant digit, and another also be alternative,with a zero in the last significant digit
 * Display them with Integer.toBinaryString()
 * Take these two values and combine them in all possible ways using the bitwise operators, and dispaly
 * the result using Integer.toBinary.String()
 */
public class Chap3Prac10 {
    public static void main(String[] args){
        int i1 = 0x2f;
        int i2 = 0x2e;
        P.print("i1: "+Integer.toBinaryString(i1));
        P.print("i2: "+Integer.toBinaryString(i2));
        P.print("i1 & i2: "+Integer.toBinaryString(i1&i2));
        P.print("i1 | i2: "+Integer.toBinaryString(i1|i2));
        P.print("i1 ^ i2: "+Integer.toBinaryString(i1^i2));
        P.print("~i1: "+Integer.toBinaryString(~i1));
        P.print("~i2: "+Integer.toBinaryString(~i2));
    }
}

/**
 * Created by Sandy.Liu on 2018/7/12.
 * Thinking in java, version 4, chapter 3, practice 11
 * Right shift a hex number which has digital 1 in the highest place, until all of its binary positions
 * are out of number 1. Display result every step.
 */
public class Chap3Pra11RightShift {
    public static void main(String[] args){
        int i = 0x10000000;
        print("i: ",i);
        for(int j=0;j<29;j++){
            print("i>>=1: ",i>>=1);
        }
    }


    static void print(String s, int i){
        P.print(s+"int: "+i+", binary:
"+ Integer.toBinaryString(i));
    }
}

/**
 * Created by Sandy.Liu on 2018/7/12.
 * Thinking in java, version 4, Chapter 3, practice 12
 *Start with a number that is all binary ones. Left shift it, then use the unsigned right shift operator to right shift
 * through all of its binary positions, each time displaying the result using Integer.toBinaryString().
 */
public class Chap3Prac12UnsignedRightShift {
    public static void main(String[] args){
        int i = 0xffff;
        P.print("int i: "+i +", binary i: "+ Integer.toBinaryString(i));
        i<<=1;
        P.print("i<<1: int i: "+i +", binary i: "+ Integer.toBinaryString(i));
        for(int j = 0;j<17;j++){
            i>>>=1;
            P.print("i>>>1: "+"int i: "+i+" , Binary: "+Integer.toBinaryString(i));
        }
    }

}

/**
 * Created by Sandy.Liu on 2018/7/13.
 * Thinking in java, chapter 3, practice 13
 * Write a method that displays char values in binary form.
 * Demonstrate it using several different characters.
 */
public class Chap3Prac13CharToBinary {
    public static void main(String[] args){
        char c=‘c‘;
       print("c: ", c);
        char c1 = ‘a‘;
        print("a: ", c1);
        char c2 = ‘b‘;
        print("0: ",c2);
        char c3=‘A‘;
        print("A: ", c3);
        for(int i=0;i<26;i++){
            print(""+i+": ",(char)i);
        }

    }

    static void print(String s, char c){
        P.print(s+ Integer.toBinaryString(c));
    }
}

/**
 * Created by Sandy.Liu on 2018/7/17.
 * Write a method which receive two string values, use all kind of boolean values‘s compare relations to compare these
 * two values, and print the result. Use equals() to test when use == and !=.
 * Use different string values to test this method.
 */
public class Chap3Prac14StringValue {
    static void StringValuesTest(String s1, String s2){
        P.print(s1 +"=="+s2+": "+(s1==s2));
        P.print(s1+"!="+s2+": "+(s1!=s2));
        P.print(s1+".equals("+s2+"): "+s1.equals(s2));
        P.print(s2+".equals("+s1+"): "+s2.equals(s1));
        P.print(s1+"+"+s2+": "+(s1+s2));
    }
    public static void main(String[] args){
        StringValuesTest("one", "two");
        StringValuesTest("one", "one");
        StringValuesTest("one", "onetwo");
    }
}