Java语言程序设计第6章习题参考答案

习题六参考答案importjava.util.Scanner;publicclassXT_1_score{publicstaticvoidmain(String[]args){importjava.util.Scanner;publicclassXT_1_score{publicstaticvoidmain(String[]args){//TODOAuto-generatedmethodstubdoublescore[]=newdouble[5];System.out.println("请分别输入数学、语文、英语、物理、化学的成绩（数字之间用空格格开）：");doublesum=0,average=0;Scannerin=newScanner(System.in);inti;for(i=0;i<5;i++)score[i]=in.nextDouble();for(i=0;i<5;i++)sum+=score[i];average=sum/5;System.out.println("String.format("%.1f"average));}}50100分、importjava.util.Scanner;publicclassXT_2_score_sore{publicstaticvoidmain(String[]args){//TODOAuto-generatedmethodstubimportjava.util.Scanner;publicclassXT_2_score_sore{publicstaticvoidmain(String[]args){//TODOAuto-generatedmethodstubdoublescore[]=newdouble[50];inta=0,b=0,c=0,d=0,e=0,f=0,i;System.out.println("请依次输入50名学生的成绩（用空格隔开）：");Scannerbr=newScanner(System.in);for(i=0;i<50;i++)score[i]=br.nextDouble();for(i=0;i<50;i++){if(score[i]==100)a++;a++;if(score[i]>=90&&score[i]<=99)b++;if(score[i]>=80&&score[i]<=89)c++;if(score[i]>=70&&score[i]<=79)d++;if(score[i]>=60&&score[i]<=69)e++;if(score[i]<60)f++;}System.out.println("成绩为100分的个数："+a);System.out.println("成绩为90-99分的个数："+b);System.out.println("成绩为80-89分的个数："+c);System.out.println("成绩为70-79分的个数："+d);System.out.println("成绩为60-69分的个数："+e);System.out.println("成绩为不及格的个数："+f);}}importjava.util.Arrays;importimportjava.util.Arrays;importjava.util.Scanner;classXT_3_string{publicstaticvoidmain(String[]args){//TODOAuto-generatedmethodstubSystem.out.println("请输入字符串数组中的字符：");Scannerin=newScanner(System.in);Stringstr=in.next();chararray[]=newchar[str.length()];for(inti=0;i<str.length();i++){array[i]=str.charAt(i);}Arrays.sort(array);System.out.println("最大值為：array[str.length(1]);System.out.println("最小值為：array[0]);}}使用键盘输入一个字符串，编写程序统计这个字符串中的字母、空格和数字的个数。ScannerinStringstr==newScanner(System.in);in.nextLine();for(inti=0;i<str.length();i++){importjava.util.Scanner;classXT_4_string{publicstaticvoidmain(String[]args){//TODOAuto-generatedmethodstubinta=0,b=0,c=0;System.importjava.util.Scanner;classXT_4_string{publicstaticvoidmain(String[]args){//TODOAuto-generatedmethodstubinta=0,b=0,c=0;System.out.println("请输入一段字符串：");chararray=str.charAt(i);if((array>='a'&&array<='z')||(array>='A'&&array<='Z'))a++;if(array>='0'&&array<='9')b++;if(array=='')c++;}System.out.println("字母的个数：a);System.out.println("数字的个数：b);System.out.println("空格的个数：c);}}importjava.io.BufferedReader;importjava.io.IOException;importjava.io.InputStreamReader;importimportjava.io.BufferedReader;importjava.io.IOException;importjava.io.InputStreamReader;importjava.util.Scanner;publicclassXT_5_nixu{publicstaticvoidmain(String[]args)throwsIOException{//TODOAuto-generatedmethodstubSystem.out.println("请输入数组的长度：");BufferedReaderbr=newBufferedReader(newInputStreamReader(System.in));Stringm;m=br.readLine();intarray[]=newint[Integer.parseInt(m)];System.out.println("请输入数组的元素(用空格隔开)：");Scannerin=Scannerin=newScanner(System.in);for(inti=0;i<Integer.parseInt(m);i++){array[i]=in.nextInt();}System.out.println("逆序输出：");for(inti=Integer.parseInt(m)-1;i>=0;i--)System.out.print(array[i]+"");}}importjava.util.Scanner;publicclassXT_6_YangHSJ{importjava.util.Scanner;publicclassXT_6_YangHSJ{publicstaticvoidyanghui(inta[][],intr){for(inti=0;i<r;i++){for(intj=0;j<a[i].length;j++){if(i==0||j==0||j==a[i].length-1)a[i][j]=1;elsea[i][j]=a[i-1][j-1]+a[i-1][j];}}System.out.println(r+"行杨辉三角为:");//输出杨辉三角for(inti=0;i<r;i++){for(intk=r-i;k>0;k--)System.out.print(" for(intj=0;j<a[i].length;j++){.t]+" }System.out.println();}}publicstaticvoidmain(String[]args){//TODOAuto-generatedmethodstub{System.out.println("请输入杨辉三角的行数:");Scannerinput=newScanner(System.in);intintr=input.nextInt();input.close();inta[][]=newint[r][];for(inti=0;i<r;i++)a[i]=newint[i+1];yanghui(a,r);}}}importjava.util.Scanner;publicclassXT_6_7{publicstaticvoidmain(String[]args){{intcount=10;floatarray[]=newfloat[10];importjava.util.Scanner;publicclassXT_6_7{publicstaticvoidmain(String[]args){{intcount=10;floatarray[]=newfloat[10];System.out.println("请输入数组的元素(用空格隔开)：");Scannerin=newScanner(System.in);for