Java_1_ basic data types and arrays

The basic data types for Java are from low to high by the precision level:

byte short char int long float double

Experiment One:

Conversions between data: char and int (output Greek alphabet)

Public class Program2_1 {
public static void Main (String args[]) {
int startposition = 0, endposition = 0;
char Cstart = ' α ', cend = ' ω ';
startposition = (int) Cstart;
endposition = (int) cend;
System.out.println ("Greek alphabet \ ' alpha" + "\ ' in the order position of the Unicode table:" +startposition);
System.out.println ("Greek alphabet:");
for (int i = startposition; i<= endposition; i++) {
char c = ' + ';
C = (char) i;
System.out.println ("" +c);
if ((i-startposition+1)%10==0)
System.out.println ("");
}
}
}

To give a reverse one:

public class Program2_test1 {
public static void Main (String args[]) {
int startposition = 0, endposition = 0;
Char Cstart = ' A ', cend = ' Z ';
startposition = (int) Cstart;
endposition = (int) cend;
System.out.println (the "English letter \ ' a\ ' position in Unicode is:" +startposition);
System.out.println ("The English alphabet is as follows:");
for (int i = startposition; I <= endposition; i++) {
char c = ' + ';
c = (char) i;
System.out.println ("+c");
}
}
}

Experiment Two:

An array of references and elements:

public class Program2_2 {
public static void Main (String args[]) {
int [] a = {100,200,300};
System.out.println (a.length);
System.out.println (a);
int b[][] = {{1},{1,1},{1,2,1},{1,3,3,1},{1,4,6,4,1}};
System.out.println (b.length);
System.out.println (b[4][2]);
B[4] = A;
System.out.println (b[4][2]);
}
}

Relevant knowledge points:

Arrays are reference variables, for

int a[] = {1,2,3},b [] = {4,5};

The array variables A and B hold the reference, the value of a is the value of 0x35ce36,b is 0X757AEF;

For a one-dimensional array, the value of "array name. Length" is the number of elements in the array, and for a two-dimensional array, the value of "array name. Length" is the number of one-dimensional arrays that he contains.

Experiment Three:

Facilitates and replicates arrays:

Import Java.util.Arrays;
public class Program2_3 {
public static void Main (String args[]) {
int [] a = {1,2,3,4,500,600,700,800};
int [] b,c,d;
System.out.println (Arrays.tostring (a));
b = arrays.copyof (a,a.length);
System.out.println (arrays.tostring (b));
c = arrays.copyof (a,4);
System.out.println (Arrays.tostring (c));
D = Arrays.copyofrange (a,4,a.length);
System.out.println (arrays.tostring (d));
C[C.LENGTH-1] =-100;
D[D.LENGTH-1] =-200;
System.out.println (Arrays.tostring (a));
}
}

To give a reverse one:

Import Java.util.Arrays;
public class Program2_test3 {
public static void Main (String args[]) {
int [] a = {1,2,3,4,5,100,200,300,400,500};
int [] b,c,d;
b = arrays.copyof (A, a.length);
System.out.println (arrays.tostring (b));
c = arrays.copyof (a,5);
System.out.println (Arrays.tostring (c));
D = Arrays.copyofrange (a,5,a.length);
System.out.println (arrays.tostring (d));

}
}

Java_1_ basic data types and arrays