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Basics of Java Programming - Part 1



  • Datatypes in Java

    • int 4 bytes
      • short int 2 bytes
      • long int 8 bytes
      • byte 1 byte
    • float  4 bytes
    • double 8 bytes
    • char 2 bytes

  • Character to ASCII conversion in JAVA

        class CharToASCII {
public static void main(String a[]) {
char c1 = 'A';
char c2 = 'a';
System.out.print((int)c1); // OUTPUT: 65
System.out.print((int)c2); // OUTPUT: 97
System.out.print((char)66); // OUTPUT: B  --> ASCII to int conversion
          }
       }


  • "printf" is also available in JAVA

          class PrintfInJava {
            public static void main(String a[]) {
int i = 4;
int j = 7;
                 int k = i+j;
System.out.printf("Addition of %d and %d is %d", i, j, k); // OUTPUT: 65
           }
       }

  • Binary Literals

        public class BinaryLiterals {
public static void main(String a[]) {
// i, j and k are same representation
int i = 0b10000000;
int j = 0B10000000;
int k = 0b100_00_000;
System.out.printf("value of i is %d, j is %d and k is %d", i, j, k); 
}
      }
      //OUTPUT: value of i is 128, j is 128 and k is 128

  • Post increment

       public class PostIncrement {
public static void main(String a[]) {
int i = 10;
i = i++;
/*
           i = i++; is similar to:
          int temp;
          temp = i;
           i++;
           i = temp;
         //OUTPUT 10
*/
System.out.println("value of i is " + i );
int j = 7;
int k;
k = j++;
System.out.println("\n value of k is: "+ k + " and j is: "+ j );
}
     }

     //OUTPUT: 
     // value of i is 10
    //  value of k is: 7 and j is: 8

  • Bitwise left and right shift operator

       public class LeftAndRightShiftOps {
public static void main(String a[]) {
int i = 25; // Binary  1 1 0 0 1
int j = i << 2; // Binary 1 1 0 0 1 0 0
int k = i >> 2; // Binary 1 1 0
System.out.printf("value of j is %d \nvalue of k is %d", j, k);
}
     }

    //OUTPUT: 
   // value of j is 100 
  // value of k is 6

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