Section fourth (conversion of basic types)

/*about shaping data in the Java language: Byte 1byte (8bit) -128 ~ 127 short 2byte int 4byte long 8byte integer type There are three ways to express 1. Decimal 2. Octal begins with 0 in 3. Hex starts with 0x*/ Public classdatatypetest01{ Public Static voidMain (string[] args) {//decimal        inti =Ten;//Common Types//octal        intj =010; //hexadecimal        intK =0x10; System. out. println ("i ="+i); System. out. println ("j ="+j); System. out. println ("k ="+k); //assigns an int type 100 literal value to the M variable        intm = -; //assigns an int type 150 literal value to a long type N//capacity of type int is less than type long//The data class conversion already exists by default, but is "automatic type conversion"        Longn = Max; //because "L" appears, 160 is considered a long type.//The following program does not have a type conversion, just a normal assignment operation        Longx =160L; //you can convert an int type to a long type "automatic type conversion"        Longy =234233633;//If the value of type int is less than 2^31-1//when to use "L" or "L", it is recommended to use "L "//if the value is greater than 2^31-1, use L and is a long type        Longt =8797979L; System. out. println ("L ="+t); }}

/*byte type*/ Public classdatatypetest02{ Public Static voidMain (string[] args) {Longi =1000L; //cannot auto type conversion//you need to force type conversions, add mandatory type conversions ()//after adding (int), the compilation passes, but the program may lose precision at run time, so be sure to use it carefully//large-capacity long-like small-volume conversion requires forced type conversion        intj = (int) I; //byte value range (-128 ~ 127) As long as the range is not exceeded        byteK =Ten; bytem =127; //byte n = 128; Error wording out of range//Short value range ( -32768 ~ 32767)         Shortx =23423; //Char Value range (0 ~ 65535)//Summary: If the integer does not exceed the Byte,short,char range, you can assign the integer value to Byte,short,char        Chary = -; CharU =65535; intv =58787; CharW = (Char) v; System. out. println ("j ="+ j +"u ="+ U +"W ="+W); }}

/*about floating-point float 4 bytes double 8 bytes*/ Public classdatatypetest03{ Public Static voidMain (string[] args) {Doublei =1.2; //Forcing type conversions        floaty = (float) I; //Automatic assignment operator        floatx =1.2F; System. out. println ("i ="+ i +"y ="+ y +"x ="+x); }}

/*Boolean types in Java 1. There are only two values: True/false not 0 and 1 2. Mainly used in logical operators and conditional control statements*/ Public classdatatypetest04{ Public Static voidMain (string[] args) {//Boolean i = 1;Boolean sex=true; if(Sex) {System. out. println ("Men"); } Else{System. out. println ("Women"); } System. out. println ("sex ="+sex); }}

/*Byte,short,char do mixed operations, you need to convert to int before doing the operation.*/ Public classdatatypetest05{ Public Static voidMain (string[] args) {bytei =Ten;  Shortj = -; intK = i +J; bytem = (byte) (i +j); System. out. println ("k ="+ K +"m ="+m); /*Java programs run at the time of two times 1. Compile period 2. Run time at compile stage just know i+j is int type int type cannot be assigned directly to byte type*/                byten = -; }}

Section fourth (conversion of basic types)