Đáp án 42 bài tập lập trình Java cơ bản

o nguyen to");
	}
	//Sap xep cac cot theo thu tang dan
	public static void sortColum(int[][] A, int n, int m){
	int i,j,temp;
	for(j=0 ; j<m ; j++){
	for(i=1 ; i<n ; i++){
	if(A[i-1][j]>A[i][j]){
	temp= A[i-1][j];
	A[i-1][j]= A[i][j];
	A[i][j]= temp;
	}
	}
	}
	inMT(A, n, m);
	}
 public static void main(String[] args) {
 System.out.print("Nhap so hang n=");
	int n= nhap();
	System.out.print("Nhap so cot m=");
	int m= nhap();
	int [][] A= new int[n][m];
	int i,j;
	for(i=0 ; i<n ; i++){
	for(j=0 ; j<m ; j++){
	System.out.println("Nhap phan tu thu A["+(i+1)+"]["+(j+1)+"]= ");
	A[i][j]= nhap();
	}
	}
	System.out.println("Ma tran nhap vao: ");
	inMT(A, n, m);
	for(i=0 ; i<n ; i++){
	for(j=0 ; j<m ; j++){
	if(A[i][j]==findMaxMT(A, n, m))System.out.println("\nPhan tu o hang "+i+" cot "+j+" dat Max: A["+i+"]["+j+"]= "+A[i][j]);
	}
	}
	phanTuSNT(A, n, m);
	sortColum(A, n, m);
 }
}
Bài 25 :
package bai25;
public class Main {
 public static boolean checkSNT(int n){
	if(n>1){
	for(int i=2;i<=Math.sqrt(n);i++){
	if(n%i==0) return false;
	}
	return true;
	}
	else return false;
	}
 public static boolean testSoThuanNghich(int n){
	StringBuilder xau= new StringBuilder();
	String str= ""+n;
	xau.append(str);
	String check= ""+xau.reverse();
	if(str.equals(check)) return true;
	else return false;
	}
 public static boolean nguyenTo(int n){
	while(n!=0){
	if(!checkSNT(n%10)) return false;
	n/= 10;
	}
	return true;
	}
 public static void main(String[] args) {
 int i,count= 0;
	System.out.println("cac so tu 5-7 chu so thoa man dieu kien la: ");
	for(i=22223 ; i<7777777 ; i+=2){
	if(checkSNT(i) && nguyenTo(i) && testSoThuanNghich(i)){
	System.out.println(" "+i); count++;
	}
	}
	System.out.println("\n Co "+count+" so thoa man");
 }
}
Bài 26 :
package bai26;
public class Main {
 public static boolean checkSNT(int n){
	if(n>1){
	for(int i=2;i<=Math.sqrt(n);i++){
	if(n%i==0) return false;
	}
	return true;
	}
	else return false;
	}
 public static boolean testSoThuanNghich(int n){
	StringBuilder xau= new StringBuilder();
	String str= ""+n;
	xau.append(str);
	String check= ""+xau.reverse();
	if(str.equals(check)) return true;
	else return false;
	}
 public static boolean nguyenToTong(int n){
	int T= 0;
	while(n!=0){
	T+= n%10;
	if(!checkSNT(T)) return false;
	n/= 10;
	}
	return true;
	}
 public static void main(String[] args) {
 int i,count= 0;
	System.out.println("cac so tu 5-7 chu so thoa man dieu kien la: ");
	for(i=22223 ; i<7777777 ; i+=2){
	if(checkSNT(i) && nguyenToTong(i) && testSoThuanNghich(i)){
	System.out.println(" "+i); count++;
	}
	}
	System.out.println("\n Co "+count+" so thoa man");
 }
}
Bài 27 :
package bai27;
import java.util.Arrays;
import java.util.Scanner;
public class Main {
 public static int nhap(){
	Scanner input= new Scanner(System.in);
	boolean check= false;
	int n=0;
	while(!check){
	System.out.print(" ");
	try{
	n= input.nextInt();
	check= true;
	}catch(Exception e){
	System.out.println("Ban phai nhap so! hay nhap lai...");
	input.nextLine();
	}
	}
	return (n);
	}
 public static int viTriMaxInt(int a[], int n){
	int max= a[0];
	int key= 0;
	for(int j=0 ; j<n ; j++){
	if(max<a[j]){
	max= a[j];
	key= j;
	}
	}
	return (key);
	}
 public static void inArray(int[] a, int begin , int end){
	System.out.println();
	int i;
	for(i=begin ; i<end ; i++){
	System.out.print(" "+a[i]);
	}
	System.out.println();
	}
 public static int viTriMax2(int[] a,int n){
	int i,key=0,Max2=0;
	for(i=0 ; i<n ; i++){
	if(a[i]>Max2 && a[i]!= a[viTriMaxInt(a, n)]){
	Max2= a[i];key= i;
	}
	}return (key);
	}
	public static void themPhanTu(int[] a,int n,int pt){
	a[0]= pt;
	Arrays.sort(a);
	}
 public static void main(String[] args) {
 System.out.print("Nhap n= ");
	int n= nhap();
	int[] a= new int[n+1];
	int i;
	for(i=0 ; i<n ; i++){
	System.out.print("\n Nhap phan tu thu "+i+" = ");
	a[i]= nhap();
	}
	for(i=0 ; i<n ; i++){
	if(a[i]== a[viTriMax2(a, n)]) System.out.println(" Phan tu thu "+i+" lon thu 2 trong mang a["+i+"]= "+a[i]);
	}
	Arrays.sort(a);
	inArray(a,1,n+1);
	System.out.print("Nhap phan tu muon them pt= ");
	int pt= nhap();
	themPhanTu(a,n+1,pt);
	inArray(a,0,n);
 }
}
Bài 28 :
package bai28;
import java.util.Scanner;
public class Main {
 public static int nhap(){
	Scanner input= new Scanner(System.in);
	boolean check= false;
	int n=0;
	while(!check){
	System.out.print(" ");
	try{
	n= input.nextInt();
	check= true;
	}catch(Exception e){
	System.out.println("Ban phai nhap so! hay nhap lai...");
	input.nextLine();
	}
	}
	return (n);
	}
 public static void inMT(int[][] A, int n, int m){
	int i,j;
	for(i=0 ; i<n ; i++){
	System.out.print("\n");
	for(j=0 ; j<m ; j++) System.out.print(" "+A[i][j]);
	}
	}
 public static int findMaxMT(int[][] A, int n, int m){
	int Max= A[0][0];
	for(int i=0 ; i<n ; i++){
	for(int j=0 ; j<m ; j++){
	if(Max<A[i][j]) Max= A[i][j];
	}
	}
	return (Max);
	}
 public static void main(String[] args) {
 System.out.print("Nhap so hang n=");
	int n= nhap();
	System.out.print("Nhap so cot m=");
	int m= nhap();
	int [][] A= new int[n][m];
	int i,j;
	for(i=0 ; i<n ; i++){
	for(j=0 ; j<m ; j++){
	System.out.println("Nhap phan tu thu A["+(i+1)+"]["+(j+1)+"]= ");
	A[i][j]= nhap();
	}
	}
	//In ra ma tran nhap vao
	System.out.println("Ma tran nhap vao: ");
	inMT(A, n, m);
	//Tim phan tu max
	for(i=0 ; i<n ; i++){
	for(j=0 ; j<m ; j++){
	if(A[i][j]==findMaxMT(A, n, m))System.out.println("\nPhan tu o hang "+i+" cot "+j+" dat Max: A["+i+"]["+j+"]= "+A[i][j]);
 }
 }
}
}
Bài 29 :
package bai29;
import java.util.Scanner;
public class Main {
 public static int nhap(){
	Scanner input= new Scanner(System.in);
	boolean check= false;
	int n=0;
	while(!check){
	System.out.print(" ");
	try{
	n= input.nextInt();
	check= true;
	}catch(Exception e){
	System.out.println("Ban phai nhap so! hay nhap lai...");
	input.nextLine();
	}
	}
	return (n);
	}
 public static void horner(int a[], int n){
	int T=0,i,x;
	System.out.println("\n Nhap x= ");
	x= nhap();
	T= a[n];
	for(i=n ; i>0 ; i--){
	T= T*x + a[i-1];
	}
	System.out.println("Gia tri cua da thuc tinh theo cong thuc Horner la: "+T);
	}
 public static void inDaThuc(int a[], int n){
	int i;
	for(i=n ; i>0 ; i--){
	System.out.print(" "+a[i]+".x^"+i+" + ");
	}
	System.out.print(" "+a[0]);
	}
	public static void daoHam(int a[],int dh[], int n){
	int i;
	for(i=n ; i>0 ; i--){
	dh[i-1]= a[i]*i;
	}
	inDaThuc(dh,n-1);
	}
	public static void tongDaThuc(int a[], int n, int b[], int m){
	int i;
	System.out.println("\n Tong cua 2 da thuc A va B la: ");
	if(n>m){
	for(i=m ; i>=0 ; i--){
	a[i]+=b[i];
	}
	inDaThuc(a,n);
	}
	else
	for(i=n ; i>=0 ; i--){
	b[i]+=a[i];
	}
	inDaThuc(b,m);
	}	
 public static void main(String[] args) {
 int i;
	System.out.println("Nhap bac cua da thuc n= ");
	int n= nhap();
	int[] array= new int[n+1];
	for(i=n ; i>=0 ; i--){
	System.out.print("Nhap he so cua x^"+i+" = ");
	array[i]= nhap();
	}
	System.out.println("Da thuc A nhap vao la: ");
	inDaThuc(array, n);
	horner(array, n);
	//Tinh dao ham bac 1
	int[] dh= new int[n+1];
	daoHam(array,dh,n);
	//Tinh tong 2 da thuc
	System.out.println("\n Nhap bac cua da thuc m= ");
	int m= nhap();
	int[] array2= new int[m+1];
	for(i=m ; i>=0 ; i--){
	System.out.print("Nhap he so cua x^"+i+" = ");
	array2[i]= nhap();
	}
	System.out.println("Da thuc B nhap vao la: ");
	inDaThuc(array2, m);
	tongDaThuc(array, n, array2, m);
 }
}
Bài 31 :
import java.util.*;
public class Bai31 {
	public static String chuyenInHoa(String str){
	String s,strOutput;
	s= str.substring(0, 1);
	strOutput= str.replaceFirst(s,s.toUpperCase());
	return (strOutput);
	}
	public static String chuanHoa(String strInput){
	String strOutput="";
	StringTokenizer strToken= new StringTokenizer(strInput," ,\t,\r");
	strOutput+=""+chuyenInHoa(strToken.nextToken());
	while(strToken.hasMoreTokens()){
	strOutput+=" "+chuyenInHoa(strToken.nextToken());
	}
	return(strOutput);
	}
	public static void main(String[] args) {
	// TODO Auto-generated method stub
	Scanner input= new Scanner(System.in);
	System.out.println("Nhap vao 1 xau: ");
	String strInput= input.nextLine();
	System.out.println("Xau duoc chuan hoa la: "+chuanHoa(strInput));
	}
}
Bài 32 :
import java.util.*;
public class Bai32 {
	public static void timXauMax(String strInput){
	StringTokenizer strToken= new StringTokenizer(strInput," ,\t,\r");
	int Max,i=1,lengthStr;
	Max= strToken.nextToken().length();
	int viTriMax= i;
	while(strToken.hasMoreTokens()){
	lengthStr= strToken.nextToken().length();
	i++;
	if(Max < lengthStr){
	Max= lengthStr;
	viTriMax= i;
	}
	}
	System.out.println("Do dai xau lon nhat la: "+Max+" o vi tri "+viTriMax);
	}
	public static void main(String[] args) {
	// TODO Auto-generated method stub
	Scanner input= new Scanner(System.in);
	System.out.println("Nhap vao 1 xau: ");
	String strInput= input.nextLine();
	timXauMax(strInput);
	}
}
Bài 33 :
import java.util.*;
public class Bai33 {
	public static String doiViTri(String strInput){
	String str= Bai31.chuanHoa(strInput);
	StringTokenizer strToken= new StringTokenizer(str," ");
	String ho = strToken.nextToken();
	String hoDem = strToken.nextToken();
	String ten = strToken.nextToken();
	String strOutput= ten+" "+ho+" "+hoDem;
	return(strOutput);
	}
	public static void main(String[] args) {
	// TODO Auto-generated method stub
	Scanner input= new Scanner(System.in);
	System.out.println("Nhap vao ho ten ( ho-ho dem -ten) : ");
	String strInput= input.nextLine();
	System.out.println("Ho va ten duoc sap xep lai (ten- ho - ho dem) : 

"+doiViTri(strInput));
	}
}