Integer toString() in Java

1. The java.lang.Integer.toString() is an inbuilt method in Java which is used to return the String object representing this Integer’s value.

   Syntax :

   public static String toString()

   Parameters: The method does not accept any parameters.

   Return Value:The method returns the string object of the particular Integer value.

   Below program illustrates the Java.lang.Integer.toString() method:

   // Java program to illustrate the
   // toString() Method
   import java.lang.*;
   
   public class Geeks{
   
   public static void main(String[] args) {
   
       Integer obj = new Integer(8);
   
       //It will return a string representation
       String stringvalue1 = obj.toString();
       System.out.println("String Value= " +
                               stringvalue1);
   
   
           Integer obj3 = new Integer(10);
   
       //It will return a string representation
       String stringvalue3 = obj3.toString();
       System.out.println("String Value = " +
                               stringvalue3);
   
   }
   }
   Output:

   String Value= 8
   String Value = 10
   

2. The java.lang.Integer.toString(int a) is an inbuilt method in Java which is used to return a String object, representing the specified integer in the parameter.
   Syntax :

   public static String toString(int a)

   Parameters: The method accepts one parameter a of integer type and refers to the integer needed to be converted to string.

   Return Value: The method returns the string representation of the argument in a particular base.

   Examples:

   For base 8: 
   Input: int a = 75 
   Output: "75"
   
   For base 10:
   Input: int a = -787 
   Output: "-787"
   

   Below programs illustrate the Java.lang.Integer.toString(int a) method:
   Program 1:

   // Java program to illustrate the
   // toString(int a) method
   import java.lang.*;
   
   public class Geeks{
   
   public static void main(String[] args) {
   
       Integer obj = new Integer(8);
   
       // It will return a string representation
           // in base 8
       String stringvalue1 = obj.toString(75);
       System.out.println("String Value = " +
                               stringvalue1);
   
       Integer obj2 = new Integer(8);
   
       // It will return a string representation
           // in base 2
       String stringvalue2 = obj2.toString(6787);
       System.out.println("String Value = " +
                               stringvalue2);
   
   
           Integer obj3 = new Integer(10);
   
       // It will return a string representation
           // in base 10
       String stringvalue3 = obj3.toString(-787);
       System.out.println("String Value = " +
                               stringvalue3);
   
   }
   }
   Output:

   String Value = 75
   String Value = 6787
   String Value = -787
   

   Program 2: For decimal and string parameters.
   Note: This results in an error and as well for the absence of suitable Integer constructor.

   // Java program to illustrate the
   // Java.lang.Integer.toString(int a)method
   import java.lang.*;
   public class Geeks{
   
   public static void main(String[] args) {
       Integer obj = new Integer(8);
       String stringvalue1 = obj.toString(58.5);
       System.out.println("String Value = " +
                               stringvalue1);
   
       Integer obj2 = new Integer(8);
       String stringvalue2 = obj2.toString("317");
       System.out.println("String Value = " +
                               stringvalue2);
   
   
       // Empty constructor will result in an error
       Integer obj3 = new Integer();
       String stringvalue3 = obj3.toString(-787);
       System.out.println("String Value = " +
                               stringvalue3);
   
   }
   }

   Output:

   prog.java:8: error: incompatible types: possible 
   lossy conversion from double to int
       String stringvalue1 = obj.toString(58.5);
                                          ^
   prog.java:12: error: incompatible types: String cannot 
   be converted to int
       String stringvalue2 = obj2.toString("317");
                                           ^
   prog.java:17: error: no suitable constructor found for 
   Integer(no arguments)
       Integer obj3 = new Integer();
                      ^
       constructor Integer.Integer(int) is not applicable
         (actual and formal argument lists differ in length)
       constructor Integer.Integer(String) is not applicable
         (actual and formal argument lists differ in length)
   Note: Some messages have been simplified; recompile with 
   -Xdiags:verbose to get full output
   3 errors

3. The java.lang.Integer.toString(int a, int base) is an inbuilt method in Java which is used to return a string representation of the argument a in the base, specified by the second argument base. If the radix/base is smaller than Character.MIN_RADIX or larger than Character.MAX_RADIX, then the base 10 is used. The ASCII characters which are used as digits: 0 to 9 and a to z.
   Syntax:

   public static String toString(int a, int base)

   Parameter: The method accepts two parameters:

   • a: This is of integer type and refers to the integer value that is to be converted.
   • base: This is also of integer type and refers to the base that is to be used while representing the strings.

   Return Value: The method returns a string representation of the specified argument in the specified base.

   Examples:

   Input: a = 71, base = 2
   Output: 1000111
   
   Input: a = 314, base = 16
   Output: 13a
   

   Below programs illustrate the Java.lang.Integer.toString(int a, int base) Method:
   Program 1:

   // Java program to illustrate the
   // toString(int, int) Method
   import java.lang.*;
   
   public class Geeks{
   
   public static void main(String[] args) {
   
           Integer a = new Integer(10);
   
       // It returns a string representation
           // in base 2
       String returnvalue = a.toString(5254, 2);
       System.out.println("String Value = " +
                               returnvalue);
   
       // It returns a string representation
           // in base 8
       returnvalue = a.toString(35, 8);
       System.out.println("String Value = " +
                               returnvalue);
   
       // It returns a string representation
           // in base 16
       returnvalue = a.toString(47, 16);
       System.out.println("String Value = " +
                               returnvalue);
   
       // It returns a string representation
           // in base 10
       returnvalue = a.toString(451, 10);
       System.out.println("String Value = " +
                               returnvalue);
   }
   }
   Output:

   String Value = 1010010000110
   String Value = 43
   String Value = 2f
   String Value = 451
   

   Program 2:

   // Java program to illustrate the
   // toString(int, int) Method
   import java.lang.*;
   
   public class Geeks{
   
   public static void main(String[] args) {
   
           Integer a = new Integer(10);
   
       // It returns a string representation
           // in base 2
       String returnvalue = a.toString(-525, 2);
       System.out.println("String Value = " +
                               returnvalue);
   
       // It returns a string representation
           // in base 8
       returnvalue = a.toString(31, 8);
       System.out.println("String Value = " +
                               returnvalue);
   
       // It returns a string representation
           // in base 16
       returnvalue = a.toString(28, 16);
       System.out.println("String Value = " +
                               returnvalue);
   
       // It returns a string representation
           // in base 10
       returnvalue = a.toString(29, 10);
       System.out.println("String Value = " +
                               returnvalue);
   }
   }
   Output:

   String Value = -1000001101
   String Value = 37
   String Value = 1c
   String Value = 29