英文名:Introduction to Java Programming and Data Structures, Comprehensive Version, 11th Edition
7.1
import java.util.Scanner;publicclassbook{publicstaticvoidmain(String[] args){
Scanner input =newScanner(System.in);
System.out.print("Enter the number of students: ");int num = input.nextInt();int[] scores =newint[num];int best =0;
System.out.print("Enter "+num+" scores: ");for(int i=0;i<num;i++){
scores[i]=input.nextInt();if(scores[i]>best)
best=scores[i];}char[] grades={'A','B','C','D'};for(int i=0;i<num;i++)
System.out.printf("Student %d score is %d and grade is %c\n",i,scores[i],scores[i]==best?'A':grades[(best-scores[i]-1)/10]);}}
import java.util.Scanner;publicclassbook{publicstaticvoidmain(String[] args){
Scanner input =newScanner(System.in);
System.out.print("Enter 10 doubles: ");double[] ass =newdouble[10];for(int i=0;i<10;i++)
ass[i]=input.nextDouble();
System.out.println("The average is "+average(ass));}publicstaticintaverage(int[] array){int sum =0;int len = array.length;for(int value : array) sum += value;return sum/len;}publicstaticdoubleaverage(double[] array){double sum=0.0;int len = array.length;for(double ass : array) sum+=ass;return sum/len;}}
7.9
import java.util.Scanner;publicclassbook{publicstaticvoidmain(String[] args){
Scanner input =newScanner(System.in);
System.out.print("Enter 10 doubles: ");double[] ass =newdouble[10];for(int i=0;i<10;i++)
ass[i]=input.nextDouble();
System.out.println("The minimum number is "+min(ass));}publicstaticdoublemin(double[] array){double ss = array[0];for(double v : array){if(v < ss)
ss = v;}return ss;}}
7.10
import java.util.Scanner;publicclassbook{publicstaticvoidmain(String[] args){
Scanner input =newScanner(System.in);
System.out.print("Enter 10 doubles: ");double[] ass =newdouble[10];for(int i=0;i<10;i++)
ass[i]=input.nextDouble();
System.out.println("The lowest index is "+indexOfSmallestElement(ass));}publicstaticintindexOfSmallestElement(double[] array){int ss =0;for(int i=0;i<array.length;i++){if(array[i]<array[ss])
ss=i;}return ss;}}
7.11
import java.util.Scanner;publicclassbook{publicstaticvoidmain(String[] args){
Scanner input =newScanner(System.in);
System.out.print("Enter 10 doubles: ");double[] ass =newdouble[10];for(int i=0;i<10;i++)
ass[i]=input.nextDouble();
System.out.println("The mean is "+mean(ass));
System.out.println("The standard deviation is "+deviation(ass));}publicstaticdoubledeviation(double[] x){double sum=0;double mean=mean(x);for(double v:x)sum+=Math.pow(v-mean,2);return Math.sqrt(sum/(x.length-1));}publicstaticdoublemean(double[] x){double sum=0;for(double v : x) sum += v;return sum/x.length;}}
publicclassbook{publicstaticvoidmain(String[] args){
System.out.println("The random number is "+getRandom(1,1,4,5,1,4,1,9,1,9,8,1,0));}publicstaticintgetRandom(int... numbers){int jb=(int)(Math.random()*54)+1;while(inArray(numbers,jb))
jb=(int)(Math.random()*54)+1;return jb;}publicstaticboolean inArray (int[] ass,int dick){for(int value : ass){if(value == dick)returntrue;}returnfalse;}}