Summary of the most commonly used variable definitions in Java

Java most commonly used data types have basic data types, string objects, arrays, basic data types are divided into: numeric (including shaping and floating-point type), character type, Boolean type, the following a simple program to summarize these data types

1  Public classJavadatacreate {2      Public Static voidMain (string[] args) {3         /*define basic Variable type start*/4         //integer variable definition5         intx,y=56;6x=68;7System.out.println ("1. Decimal integer variable x, y values are:" +x+ "" +y);8         //floating-point variable definition9         floata=25.856f;//single-precision floating-point number definition, must be followed by FTen         Doubleb=58.378;//double-precision floating-point number definition, can be added after the D can also not add OneSystem.out.println ("2." The value of the floating-point number, a, and a, respectively: "+a+" "+b); A         //character-type variable definition -         CharC= ' a '; -         Chard=98;//you can define any character with a number in a Unicode table theSystem.out.println ("3. Character variable c,d:" +c+ "" +d+ "corresponding Unicode table numbers are:" + (int) c+ "" + (int) d); -         //Boolean type variable definition -         BooleanE=true, f=false; -System.out.println ("4. Boolean variable e,f:" +e+ "" +f); +         /*define basic variable type End*/ -         /*Defining Constants*/ +         Final Doublepi=3.142; ASystem.out.println ("The value of the constant pi is:" +PI); at         //constants can only be assigned once, and are generally named with uppercase -         /*string creation and assignment*/ -         Charg[]={' y ', ' e ', ' s ', '! '}; -String h=NewString (g); -         //Method 1, create a string object from a character array and initialize -String i=NewString ("hello!"); in         //Method 2, create a string object directly and initialize it, and Method 1 is equivalent - String J; toj= "Javadata"; +         //Method 3, reference string constants to create string variables, they all point to the same memory -System.out.println ("string h:" +h); theSystem.out.println ("String I:" +i); *System.out.println ("String J:" +j); $j= "Javase";Panax NotoginsengSystem.out.println ("These three method-defined string variables can be re-assigned, such as the J-value is:" +j); -         /*array Definition and assignment*/ the         intk[]; + String l[]; A         //declares two arrays, which are shaped and string, but cannot be used directly thek=New int[5]; +L=NewString[8]; -         //now that the array is allocated memory space, you can use the $         intm[]=New int[12]; $         //It is now declared that the array is allocated space at the same time that it can be used directly -         intn[]=New int[]{1,2,3,4,5}; -         into[]={6,7,8,9}; the         //This is done in both ways . -         //Simple to useWuyi          for(x=0;x<5;x++){ the             //Cyclic Assignment -k[x]=x; Wu         } -          for(x=0;x<5;x++){ About             //Loop Output $System.out.println (the value of the "+ (x+1) +" element of the array k,n is: "+k[x]+" "+n[x]); -             if(x<4){ -System.out.println (the value of the "+ (x+1) +" element of the "array O" is: "+o[x]); -             } A         } +         //Two-dimensional arrays are declared in the same way as one-dimensional arrays the         intp[][]={{1,2,3,8},{4,8,9,89},{16,5,23,36}}; -          for(x=0;x<p.length;x++){ $             //outer loop for traversing rows the              for(y=0;y<p[x].length;y++){ the                 //Inner loop for traversing all elements of each row theSystem.out.print (p[x][y]+ ""); the             } - System.out.println (); in             //line Break the         } the     } About}

These are the most basic in Java, accumulate a bit more, and hope to be able to use later

Summary of the most commonly used variable definitions in Java