Organize positions of a vector

Java offers different ways to copy content from one array to another:

The most appropriate strategy in this case is arraycopy where you can define exactly the positions you want to copy with just one row, the best performance, and no need to import any library additional, that is, easy and efficient.

public class Exercicio6 {
  public static void main(String[] args) {
    float somaV1 = 0, somaV2 = 0;
    float[] vetor1 = {4.3f, 2.5f, 4.7f};
    float[] vetor2 = {5.7f, 5.8f, 3.7f};

    for(int i = 0; i < vetor1.length; i++) {
      somaV1 += vetor1[i];
      somaV2 += vetor2[i];
    }

    System.out.print("Vetor 1 [" + vetor1[0] + ", " + vetor1[1]);
    System.out.println(", " + vetor1[2] + "] Soma = " + somaV1);
    System.out.print("Vetor 2 [" + vetor2[0] + ", " + vetor2[1]);
    System.out.println(", " + vetor2[2] + "] Soma = " + somaV2);

    float[] vetor3 = new float[6];

    if (somaV1 > somaV2) {
      System.arraycopy(vetor1, 0, vetor3, 0, vetor1.length);
      System.arraycopy(vetor2, 0, vetor3, 3, vetor2.length);
      System.out.println("\nVetor 1 com maior soma, resultado final:\n");
      System.out.print("Vetor 3 [" + vetor3[0] + ", " + vetor3[1] + ", " + vetor3[2]);
      System.out.print(", " + vetor3[3] + ", " + vetor3[4] + ", " + vetor3[5] + "]");
    } else {
      System.arraycopy(vetor2, 0, vetor3, 0, vetor2.length);
      System.arraycopy(vetor1, 0, vetor3, 3, vetor1.length);
      System.out.print("\nVetor 2 com maior soma, resultado final:\n");
      System.out.print("Vetor 3 [" + vetor3[0] + ", " + vetor3[1] + ", " + vetor3[2]);
      System.out.print(", " + vetor3[3] + ", " + vetor3[4] + ", " + vetor3[5] + "]");
    }
  }
}

Run the code online: link

The only thing that may be stranger in using arraycopy are the parameters that might confuse you, but here is a brief explanation of what each means in the order they are passed:

Used in the example:

System.arraycopy(vetor1, 0, vetor3, 0, vetor1.length);

vector1 will be copied, from position zero , to vector3 , starting at position zero , by making a full size ( length length ) copy of vector1 .

System.arraycopy(vetor2, 0, vetor3, 3, vetor2.length);

vector2 will be copied, from position zero , to vector3 , starting at position three , by making a full size ( length length ) copy of vector2 .

To copy vectors using for :

//Criando um vetorB do mesmo tamanho do vetorA
int [] vetorB = new int[vetorA.length];

//O vetorB recebe todos os dados do vetorA
for (int i=0; i < vetorA.length; i++) {
    vetorB[i] = vetorA[i];
}
//Exibe os dados do vetorB copiados do vetorA
for (int i=0; i < vetorB.length; i++) {
    System.out.println("vetorB[" + i + "] = " + vetorB[i]);
}

To make a vector copy using the native method clone() is very simple:

int [] vetorB = vetorA.clone();

Using the java.util.Arrays library you can use copyOf :

import java.util.Arrays;

int [] vetorB = Arrays.copyOf(vetorA, vetorA.length);

More information: link

I hope this helps ...

Good Luck!

One way to do this is to use the arraycopy after checking which sum is greater. To use the method you need to specify some parameters, as indicated in the documentation :

public static void arraycopy(Object src, int srcPos, Object dest, int
destPos, int length)

The arguments src and dest represent the origin and destination vectors, respectively. The srcPos argument is the starting position in the array source. The destPos argument is the starting position in the array target. Finally, length is used to specify the number of elements to be copied.

Here's how it would look:

 if (soma1 > soma2) {

     System.arraycopy(vector1, 0, vector3, 0, vector1.length);
     System.arraycopy(vector1, 0, vector3, vector1.length, vector2.length);

 } else {

     System.arraycopy(vector2, 0, vector3, 0, vector2.length);
     System.arraycopy(vector2, 0, vector3, vector2.length, vector1.length);
 }

See working here on Ideone .

import java.util.Arrays;

public class Test
{
    public static void main(String args[])
    {
        double[] vetor1 = new double[]{2.3, 4.7, 1.4};
        double[] vetor2 = new double[]{1.6, 6.2, 3.5};
        double[] vetor3 = new double[vetor1.length+vetor2.length];
        double soma1, soma2;
        int i;

        //Calcular a soma de cada vetor
        soma1 = soma2 = 0.0;
        for(i=0; i < vetor1.length; ++i)
            soma1 += vetor1[i];
        for(i=0; i < vetor2.length; ++i)
            soma2 += vetor2[i];

        //Verificar se os vetores estão na ordem pretendida
        if (soma2 > soma1)
        {
            //Trocar os vetores, pois estão ao contrário
            double[] vetorTmp = vetor1;
            vetor1 = vetor2;
            vetor2 = vetorTmp;
        }

        //Copiar o vetor1 para as primeiras posições do vetor3
        for(i=0; i<vetor1.length; ++i)
            vetor3[i] = vetor1[i];
        //Copiar o vetor2 para as últimas posições do vetor3
        for(i=0; i<vetor2.length; ++i)
            vetor3[i+vetor1.length] = vetor2[i];
        //Imprimir o vetor na consola
        System.out.println(Arrays.toString(vetor3));
    }
}

Use the sort () method, In the case of Java to use it import the lib java.util.Arrays.

Arrays.sort (Array);

Example:

import java.util.Arrays;

public class SortArray {

    public static void main(String[] args) {

        // initializing unsorted int array
        double myArr[] = {1.6, 6.2, 3.5, 2.3, 4.7, 1.4};

        // let us print all the elements available in list
        for (double number : myArr) {
            System.out.println("Number = " + number);
        }

        // sorting array
        Arrays.sort(myArr);

        // let us print all the elements available in list
        System.out.println("The sorted double array is:");
        for (double number : myArr) {
            System.out.println("Number = " + number);
        }
    }
}

link