Java语言程序设计（第3版）沈泽刚主编第5章课后习题答案

Java语⾔程序设计（第3版）沈泽刚主编第5章课后习题答案Java语⾔程序设计(第3版)沈泽刚主编第5章课后习题答案importScannerimportScanner;/***5.15个整数，存到⼀个数组，计算所有元素的最⼤值，最⼩值和平均值。*/publicclassIntArray{publicstaticvoidmain(String[]args){System.out.print("键盘输⼊5个整数：");Scannerinput=newScanner(System.in);int[]num=newint[5];intsum=0;intmax=Integer.MIN_VALUE;intmin=Integer.MAX_VALUE;for(inti=0;i<num.length;i++){num[i]=input.nextInt();}for(inti=0;i<num.length;i++){if(max<=num[i]){max=num[i];}if(min>=num[i]){min=num[i];}sum+=num[i];}System.out.println("max.out.println("minSystem.out.println("(1.0*sum/num.length}}1publicclassRandomTest{publicstaticvoidmain(String[]args){t3=wt[6];/int[]num4=newint[6];for(intk=0;k<100;k++){intr=(int)(Math.random()*6)+1;switch(r){case1:num3[0]++;break;case2:num3[1]++;break;case3:num3[2]++;break;case4:num3[3]++;break;case5:num3[4]++;break;case6:num3[5]++;break;}}for(intm=0;m<1000;m++){intr=(int)(Math.random()*6)+1;switch(r){case1:num4[0]++;break;case2:num4[1]++;break;case3:num4[2]++;break;case4:num4[3]++;break;case5:num4[4]++;break;case6:num4[5]++;break;}}System.out.print("100个整数中,1~6出现的次数分别为：");for(intk=0;k<num3.length;k++){System.out.print(num3[k]+"");}System.out.println();System.out.print("1000个整数中,1~6出现的次数分别为：");for(intk=0;k<num3.length;k++){System.out.print(num4[k]+"");}}}编写⼀个⽅法，求⼀个double型数组的最⼩值。importimportScanner;/***5.3double型数组的最⼩值。*/publicclassArrayDemo{publicstaticDoublemin(double[]array){doublemin=Double.MAX_VALUE;for(inti=0;i<array.length;i++){if(min>=array[i]){min=array[i];}}returnmin;}publicstaticvoidmain(String[]args){double[]array=newdouble[5];ScannerinputnewScanner(System.in.out.print("请输⼊5个double型的数字:"i<array.lengthi++){array[i]=input.nextDouble();}System.out.println("min(array}}定义⼀个有10个元素的数组，前5个元素与后5个元素交换，第1个与第10个交换，依次类推。publicclasspublicclassArrayChange{publicstaticvoidmain(String[]args){int[]array={1,2,3,4,5,6,7,8,9,10};for(intarr:array){System.out.print(arr+"");}System.out.println();for(inti=0;i<array.length/2;i++){inttemp=array[i];array[i]=array[array.length-1-i];array[array.length-1-i]=temp;}for(intarr1:array){System.out.print(arr1+"");}}}定义⼀个含有8个元素的数组，选择排序进⾏升序排序。publicclasspublicclassArraySort{publicstaticvoidmain(String[]args){int[]array={2,1,4,3,5,6,8,7};for(inti=0;i<array.length;i++){intkey=array[i];for(intj=i+1;j<array.length;j++){if(key>array[j]){inttemp=key;key=array[j];array[j]=temp;}}array[i]=key;}for(intarr:array){System.out.print(arr+"");}}}编程打印斐波那契数列的前20个数字。publicclasspublicclassFibonacci{publicstaticvoidmain(String[]args){int[]f=newint[20];f[0]=1;f[1]=1;for(inti=2;i<f.length;i++){f[i]=f[i-1]+f[i-2];}for(intf1:f){System.out.print(f1+"");}}}importArraysimportArrays;/***5.7编写⼀个⽅法，计算两个数组之和。*/publicclassSumArray{publicstaticint[]sumArray(int[]a,int[]b){intlength=Math.max(a.length,b.length);a=Arrays.copyOf(a,length);b=Arrays.copyOf(b,length);int[]r=newint[length];for(inti=0;i<length;i++){r[i]=a[i]+b[i];}returnr;}publicstaticvoidmain(String[]args){int[]a={1,2,4};int[]b={2,4,6,8};int[]c=sumArray(a,b);for(intd:c){System.out.print(d+"");}}}importArraysimportArrays;/***5.8编写⽅法，合并两个数组，并按升序返回合并后的数组。*/publicclassArrayMerge{publicstaticint[]arrayMerge(int[]a,int[]b){int[]array=newint[a.length+b.length];for(inti=0;i<a.length;i++){array[i]=a[i];}for(intj=array.length-a.length-3,k=0;j<array.length;j++,k++){array[j]=b[k];}Arrays.sort(array);returnarray;}publicstaticvoidmain(String[]args){int[]a={16,13,15,18};int[]b={9,13,15,16,29,36,100};int[]array=arrayMerge(a,b);for(intarr:array){System.out.print(arr+"");}}}importScannerimportScanner;/***5.9编写程序，使⽤⽅法求解⼀元⼆次⽅程根的个数。*/publicclassSolveQuadratic{publicstaticintsolveQuadratic(double[]eqn,double[]roots){doublediscriminant=(eqn[1]*eqn[1])-(4*eqn[0]*eqn[2]);if(discriminant>0){roots[0]=((-eqn[1])+Math.sqrt(discriminant))/(2*eqn[0]);roots[1]=((-eqn[1])-Math.sqrt(discriminant))/(2*eqn[0]);return2;}elseif(discriminant==0){roots[0]=(-eqn[1])/(2*eqn[0]);roots[1]=(-eqn[1])/(2*eqn[0]);return1;}else{return0;}}publicstaticvoidmain(String[]args){Scannerinput=newScanner(System.in);System.out.print("请输⼊⼀元⼆次⽅程的系数：a,b,c:");double[]roots=newdouble[2];double[]eqn=newdouble[3];for(inti=0;i<eqn.length;i++){eqn[i]=input.nextDouble();}System.out.println("⼀元⼆次⽅程有"+solveQuadratic(eqn,roots)+"个根");}}编写程序，筛选出2~100的所有素数。publicclasspublicclassPrimeNumber{publicstaticbooleanisPrime(intn){for(inti=2;i<n;i++){if(n%i==0){returnfalse;}}returntrue;}publicstaticvoidmain(String[]args){for(inti=2;i<=100;i++){if(isPrime(i)){System.out.print(i+"");}}}}编写程序，List1和list2数组长度相同，判断数组list1和list2是否完全相同publicclasspublicclassequals{publicstaticbooleanequals(int[]list1,int[]list2){for(inti=0;i<list1.length;i++){if(list1[i]!=list2[i]){returnfalse;}}returntrue;}publicstaticvoidmain(String[]args){int[]list1={1,2,3,4,5};int[]list2={1,2,3,4,5};int[]list3={1,2,4,3,5};System.out.println(equals(list1,list2));System.out.println(equals(list1,list3));}}编写求解约瑟夫问题。有12个⼈排成⼀圈，从1号开始报数，数到5的⼈就离开，然后继续报数，试问最后剩下的⼀个⼈是谁？publicclasspublicclassJosephus{publicstaticvoidmain(String[]args){int[]array=newint[12];for(inti=0;i<array.length;i++){array[i]=i+1;}intn=0;intcount=0;while(true){for(inti=0;i<array.length;i++){if(array[i]!=0){n++;if(n%5==0){System.out.println(array[i]+"离开！");array[i]=0;count++;}}}if(count==11){break;}}for(intj=0;j<array.length;j++){if(array[j]!=0){System.out.println(array[j]);}}}}publicclasspublicclassTwentyFour{publicstaticvoidmain(String[]args){int[]cards=newint[52];for(inti=0;i<cards.length;i++){cards[i]=i;}intsum=0,count=0while(sum!=24){for(inti=0;i<4;i++){intj=(int)(Math.random()*52);inttemp=cards[i];cards[i]=cards[j]cards[j]=temp;}sum=0;for(inti=0;i<4;i++){sum+=cards[i];}count++;}System.out.println(sum);System.out.println("count}}importimportimportScanner;Stack;/***5.14编写程序，提⽰⽤户从键盘输⼊⼀个整数，然后使⽤栈以降序输出该数的最⼩因⼦。*/publicclassUseOfStack{publicstaticvoidmain(String[]args){ScannerinputnewScanner(System.instacknew.out.print("intn=input.nextInt();intvalue=n;for(inti=2;i<n;i++){if(value%i==0){stack.push(i);value=value/ii--;}}while(!stack.isEmpty()){System.out.println(stack.pop());}}}计算两个矩阵A，B的和，差，转置。publicclassMatrixDemo{publicstaticvoidmain(String[]args){int[][]A={{1,3,5},{-3,6,0},{13,-5,7},{-2,19,25}};int[][]B={{0,-1,-2},{7,-1,6},{-6,13,2},{12,-8,-13}};int[][]sum=newint[4][3];int[][]sub=newint[4][3];int[][]tran=newint[3][4];for(inti=0;i<A.length;i++){for(intj=0;j<A[0].length;j++){sum[i][j]=A[i][j]+B[i][j];sub[i][j]=A[i][j]-B[i][j];}}for(inti=0;i<A.length;i++){for(intj=0;j<A[0].length;j++){System.out.print(sum[i][j]+"");}System.out.println();}for(inti=0;i<A.length;i++){for(intj=0;j<A[0].length;j++){System.out.print(sub[i][j]+"");}System.out.println();}for(inti=0;i<tran.length;i++){for(intj=0;j<tran[0]