Java Fundamentals Hardening Data type conversions in 22:java

Data type conversions:

(1). Automatic conversion

Low-level variables can be converted directly to advanced variables, which are called automatic type conversions. Like what:

byte b; int b; long b; float B; double b;

The above statement can be passed directly in Java.

(2). If the low-level type is char, the conversion to the advanced type (int) is converted to the corresponding ASCII value, for example:

char c = ' c '; int i = C; System.out.println ("Output:" +i);

Output: output:99

(3). For Byte/short/char three types, they are the same level, so you cannot automatically convert types to each other, and you can use forced type conversions.

Short i=99; Char c= (char) i; System.out.println ("Output:" +c);

Output: Output:c

(4). Advanced type conversions to low-level types can cause a loss of precision.

(5). Packaging transition type conversion (to compensate for the loss of accuracy in 4)

Java has 6 packaging classes are boolean,character,integer,long,float and double respectively;

String and date itself are classes, and there is no wrapper class.

e.g: float--->double

float f1 = 100.00f;

float F1 = new float (F1);

Double D1 = F1.doublevalue ();

e.g: double--->int

Double D1 = 100.00;

Double D1 = new double (d1);

int i1 = D1.intvalue ();

(6) Conversion of string types to other data types

Class Test {

public static void Main (String args[]) {

int i1 = 10;

float f1 = 3.14f;

Double D1 = 3.1415926;

Integer I1 = new Integer (i1);

float F1 = new float (F1);

Double D1 = new double (d1);

String SI1 = i1.tostring ();

String sf1 = F1 . toString ();

String SD1 = D1. toString ();

System.out.println ("SI1" +SI1);

System.out.println ("sf1" +SI1);

System.out.println ("sd1 " +SI1);

}

}

(7) Convert character type directly to other data types as numeric values

Using the character getnumericvalue (char ch) method

Java Fundamentals Hardening Data type conversions in 22:java