How to convert Strings into Numbers ?

Discussion in 'Strings, I/O, Formatting, Parsing' started by vbraojava, Oct 20, 2008.

  1. vbraojava

    vbraojava New Member

    There are two ways to convert Strings into Number :

    1. The Number subclasses that wrap primitive numeric types Byte, Integer, Double, Float, Long, and Short each provide a class method named valueOf() that converts a String to an Object of that type.

    Example : ValueOfDemo , that gets two strings from the command line, converts them to numbers, and performs arithmetic operations on the values

    public class ValueOfDemo {
    public static void main(String[] args) {

    //this program requires two arguments on the command line
    if (args.length == 2) {
    //convert strings to numbers
    float a = (Float.valueOf(args[0]) ).floatValue();
    float b = (Float.valueOf(args[1]) ).floatValue();

    //do some arithmetic
    System.out.println("a + b = " + (a + b) );
    System.out.println("a - b = " + (a - b) );
    System.out.println("a * b = " + (a * b) );
    System.out.println("a / b = " + (a / b) );
    System.out.println("a % b = " + (a % b) );
    } else {
    System.out.println("This program requires two command-line arguments.");
    }
    }
    }

    The following is the output from the program when you use 4.5 and 87.2 for the command-line arguments :

    a + b = 91.7
    a - b = -82.7
    a * b = 392.4
    a / b = 0.0516055
    a % b = 4.5


    2. Each of the Number subclasses that wrap primitive numeric types also provides a parseXXXX() method (for example, parseFloat()) that can be used to convert Strings to primitive numbers. Since a primitive type is returned instead of an object, the parseFloat() method is more direct than the valueOf() method.

    Example :

    -Above ValueOfDemo program, we could use :

    float a = Float.parseFloat(args[0]);
    float b = Float.parseFloat(args[1]);
     
  2. ukannaiah

    ukannaiah New Member

    you can use static methods of wrapper classes to convert strings into primitive numbers
    ex:int i= Integer.parseInt("10");
    sop(i)-->10
    float i= Float.parseFloat("10.6");
    ------
     
  3. sekhar.raavi

    sekhar.raavi New Member

    Double.parseDouble(String argument);
     
  4. anneroberts

    anneroberts Member

    Negative hexadecanoic corrosive numbers need aid those main ones that break inside a string. Whatever viable amount ought to make primary parsed under a string (through + "" for instance) et cetera parsed on An amount for a unartistic driver or An parseInt for An radix.
     

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