《Java语言程序设计与数据结构》编程练习答案(第五章)(四)
英文名:Introduction to Java Programming and Data Strictures, Comprehensive Version, 11th Edition
5.40
public class book {
public static void main(String[] args)
{
int zheng = 0;
int fan = 0;
for(int i=0;i<1000000;i++)
{
if(Math.random()>0.5)
zheng++;
else
fan++;
}
System.out.println("正面"+zheng+"次,反面"+fan+"次");
}
}
5.41
import java.util.Scanner;
public class book {
public static void main(String[] args)
{
Scanner input = new Scanner(System.in);
int max = 0;
int maxCount = 0;
System.out.print("Enter numbers: ");
while(true)
{
int ass = input.nextInt();
if(ass==0)
break;
else
{
if(ass>max)
{
max=ass;
maxCount=1;
}
else if(ass==max)
maxCount++;
}
}
System.out.println("The largest number is "+max);
System.out.println("The occurrence count of the largest number is "+maxCount);
}
}
5.42
import java.util.Scanner;
public class book {
public static void main(String[] args)
{
Scanner input = new Scanner(System.in);
System.out.print("Enter your target: ");
final double COMMISSION_SOUGHT = input.nextDouble();
double ass = COMMISSION_SOUGHT/0.08+5000;
int i=1;
for(i=1;i<ass;i++)
{
double ticheng = 0;
if(i<=5000)
ticheng=i*0.08;
else if(i<=10000)
ticheng=5000*0.08+(i-5000)*0.10;
else
ticheng=5000*0.08+5000*0.10+(i-10000)*0.12;
if(ticheng+5000>=COMMISSION_SOUGHT)
{
System.out.println("You need to sell $"+i);
break;
}
}
}
}
5.43
public class book {
public static void main(String[] args)
{
int count = 0;
for(int i=1;i<=6;i++)
for(int j=i+1;j<=7;j++)
{
System.out.printf("%d %d\n",i,j);
count++;
}
System.out.println("The total number of all combinations is "+count);
}
}
5.44
黑人问号
5.45
import java.util.Scanner;
public class book {
public static void main(String[] args)
{
Scanner input=new Scanner(System.in);
double sum = 0;
double sumQ = 0;
System.out.print("Enter 10 numbers: ");
for(int i=0;i<10;i++)
{
double tmp=input.nextDouble();
sum+=tmp;
sumQ+=tmp*tmp;
}
double means = sum/10.0;
double sd = Math.sqrt((sumQ-sum*sum/10.0)/9.0);
System.out.println("The mean is "+means);
System.out.println("The standard deviation is "+sd);
}
}
5.46
import java.util.Scanner;
public class book {
public static void main(String[] args)
{
Scanner input = new Scanner(System.in);
System.out.print("Enter a string: ");
String ass = input.nextLine();
System.out.print("The reversed string is ");
for(int i=ass.length()-1;i>=0;i--)
System.out.print(ass.charAt(i));
System.out.print('\n');
}
}
5.47
import java.util.Scanner;
public class book {
public static void main(String[] args)
{
Scanner input = new Scanner(System.in);
System.out.print("Enter the first 12 digits:");
String ass = input.nextLine();
if(ass.length()!=12)
System.out.println(ass+" is invalid.");
else
{
int sum=0;
for(int i=0;i<12;i++)
{
int tmp = ass.charAt(i)-'0';
if(i%2==1)
sum+=tmp;
else
sum+=3*tmp;
}
int tail = 10-sum%10;
if(tail==10)
tail=0;
System.out.println("The ISBN-13 number is "+ass+tail);
}
}
}
5.48
import java.util.Scanner;
public class book {
public static void main(String[] args)
{
System.out.print("Enter a string: ");
Scanner input = new Scanner(System.in);
String ass = input.nextLine();
int len = ass.length();
for(int i=0;i<len;i+=2)
System.out.print(ass.charAt(i));
System.out.println("");
}
}
5.49
import java.util.Scanner;
public class book {
public static void main(String[] args)
{
System.out.print("Enter a string: ");
Scanner input = new Scanner(System.in);
String ass = input.nextLine();
int len = ass.length();
ass=ass.toLowerCase();
int countV =0;
int countC = 0;
for(int i=0;i<len;i++)
{
char tmp = ass.charAt(i);
if(tmp=='a'||tmp=='e'||tmp=='i'||tmp=='o'||tmp=='u')
countV++;
else if(tmp!=' ')
countC++;
}
System.out.println("The number of vowels is "+countV);
System.out.println("The number of consonants is "+countC);
}
}
5.50
import java.util.Scanner;
public class book {
public static void main(String[] args)
{
System.out.print("Enter a string: ");
Scanner input = new Scanner(System.in);
String ass = input.nextLine();
int len = ass.length();
int countC = 0;
for(int i=0;i<len;i++) {
if (ass.charAt(i) >= 'A' && ass.charAt(i) <= 'Z')
countC++;
}
System.out.println("The number of upper case letter is "+countC);
}
}
5.51
import java.util.Scanner;
public class book {
public static void main(String[] args)
{
System.out.print("Enter the first string: ");
Scanner input = new Scanner(System.in);
String ass = input.nextLine();
System.out.print("Enter the second string: ");
String dick = input.nextLine();
int len1 = ass.length();
int len2 = dick.length();
int range = Math.min(len1,len2);
if(ass.charAt(0)!=dick.charAt(0))
System.out.println(ass+" and "+dick+" have no common prefix");
else {
System.out.print("The common prefix is ");
for (int i = 0; i < range; i++) {
if (ass.charAt(i) == dick.charAt(i))
System.out.print(ass.charAt(i));
}
System.out.println("");
}
}
}