2020-03-19 14:11:50

//Bài 1:

package hello_firstapplication;
public class Hello_FirstApplication {
    public static void main(String[] args) {
        System.out.println("Hello, this is my first appliation");
    }
    
}

2020-03-19 14:09:32

//Bài 5:

package giai_pt_bac_2;

import java.util.Scanner;

public class Giai_PT_bac_2 {

    public static void main(String[] args) {
        
        float a, b, c;
        float delta;
        float x, x1, x2;
        Scanner sc = new Scanner(System.in);
        
        System.out.println("Nhap a:");
        a = sc.nextFloat();
        System.out.println("Nhap b:");
        b = sc.nextFloat();
        System.out.println("Nhap c:");
        c = sc.nextFloat();
        
        if (a==0){
            if(b!=0){
                x = -c/b;
                System.out.println("PT co 1 nghiem x= "+x);
            }
            else {
                if(c!=0){
                    System.out.println("PT vo nghiem!");
                }
                else {
                    System.out.println("PT co vo so nghiem!");
                }
            }
        } else{
            delta = b*b - 4*a*c;
            if(delta<0) {
                System.out.println("PT vo nghiem!");
            } else if (delta==0){
                x= -b/(2*a);
                System.out.println("PT co nghiem kep x1 = x2 = "+x);
            } else if(delta>0){
                x1 = (float) ((-b-Math.sqrt(delta))/(2*a));
                x2 = (float) ((-b+Math.sqrt(delta))/(2*a));
                System.out.println("PT co 2 nghiem phan biet x1 = "+x1+", x2 = "+x2);
            }
        }
    }
    
}

2020-03-19 14:03:22

//Bài 23

//Bài 23:

package sapxepmang_selectionsort;

import java.util.Scanner;

public class SapxepMang_SelectionSort {
	
	private static void addArray(int[] A, int n) {
		Scanner sc = new Scanner(System.in);
		for(int i=0; i<n; i++) {
			System.out.print("A["+i+"]: ");
			A[i] = sc.nextInt();
		}
	}
	
	private static void showArray(int[] A, int n) {
		for(int i=0; i<n; i++) {
			System.out.println("A["+i+"]: "+A[i]);
		}
	}
	
	private static void Swap(int[] A, int a, int b) {
		int temp = A[a];
		A[a] = A[b];
		A[b] = temp;
	}
	
	private static void SelectionSort(int[] A, int n) {
		for(int i=0; i<n-1; i++) {
			int minArr = i;
			for(int j=i+1; j<n; j++) {
				if(A[minArr]>A[j]) {
					minArr = j;
				}
			}
			if(i!=minArr)
				Swap(A, minArr, i);
		}
	}

	public static void main(String[] args) {
		
		int[] A;
		int n=0;
		Scanner scn = new Scanner(System.in);
		System.out.print("Nhập số phan tu cua mang: ");
		n = scn.nextInt();
		A = new int[n];
		addArray(A, n);
                System.out.println("Mảng trước khi sắp xếp (Selection Sort)");
                showArray(A, n);
		System.out.println("Mảng sau khi sắp xếp (Selection Sort)");
		SelectionSort(A, n);
		showArray(A, n);
	}

}