Integer toString() in Java

Last Updated : 5 Dec, 2018
  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 
    // 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 
    // 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 
    // 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 
    // 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 
    // 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
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