《Java语言程序设计与数据结构》编程练习答案（第一章）

英文名：Introduction to Java Programming and Data Structures, Comprehensive Version, 11th Edition

中文版封面

在这里插入图片描述

1.1

public class book {
       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");    }}

1.2

public class book {
       public static void main(String[] args)    {
           for(int i=0; i<5; i++)            System.out.println("Welcome to java");    }}

1.3

public class book {
       public static void main(String[] args)    {
           System.out.printf("   J     A     V     V     A%n" +                          "   J    A A     V   V     A A%n" +                          "J  J   AAAAA     V V     AAAAA%n" +                          " JJ   A     A     V     A     A%n");    }}

1.4

public class book {
       public static void main(String[] args)    {
           String head1="a";        String head2="a^2";        String head3="a^3";        System.out.printf("%-8s%-8s%-8s%n",head1,head2,head3);        for(int i=1;i<5;i++)            System.out.printf("%-8d%-8d%-8d%n",i,i*i,i*i*i);    }}

1.5

public class book {
       public static void main(String[] args)    {
           double result=(9.5*4.5-2.5*3.0)/(45.5-3.5);        System.out.println(result);    }}

1.6

public class book {
       public static void main(String[] args)    {
           int sum=0;        for(int i=1;i<10;i++)            sum+=i;        System.out.println(sum);    }}

1.7

public class book {
       public static void main(String[] args)    {
           double signal = 1.0;        double sum = 0.0;        for(int i=1;i<7;i++)        {
               sum+=signal*1.0/(2*i-1);            signal*=-1.0;        }        System.out.println(4.0*sum);        sum = 0.0;        for(int i=1;i<8;i++)        {
               sum+=signal*1.0/(2*i-1);            signal*=-1.0;        }        System.out.println(4.0*sum);    }}

1.8

public class book {
       public static void main(String[] args)    {
           double pi = 3.141592654;  //1145141919810        System.out.println("The circumference is "+2.0*pi*5.5+", and the square is "+pi*5.5*5.5+".");    }}

1.9

public class book {
       public static void main(String[] args)    {
           double width = 4.5;        double height = 7.9;        System.out.println("The square is "+width*height+", and the circumference is "+2*(width+height)+".");    }}

1.10

public class book {
       public static void main(String[] args)    {
           System.out.println("The average speed is "+(14.0/1.6)/(45.0/60.0+30.0/3600.0)+" miles per hour.");    }}

1.11

public class book {
       public static void main(String[] args)    {
           double base = 312032486;        int secnum = 365*24*3600;        for(int i=1;i<6;i++)        {
               base=base+secnum/7.0-secnum/13.0+secnum/45.0;            System.out.println("The population in year "+i+" is "+(int)base);        }    }}

1.12

public class book {
       public static void main(String[] args)    {
           System.out.println("The average speed is "+24*1.6/(1+40/60.0+35.0/3500)+" kilometers per hour.");    }}

1.13

public class book {
       public static void main(String[] args)    {
           double a=3.4,b=50.2,e=44.5;        double c=2.1,d=0.55,f=5.9;        System.out.println("x is "+(e*d-b*f)/(a*d-b*c)+", and y is "+(a*f-e*c)/(a*d-b*c)+".");    }}