Using Java Pro

Calculate Rectangle Perimeter using Java

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

public class CalculateRectPerimeter

{

public static void main(String[] args)

{

int width = 0;

int length = 0;

try

{

BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

System.out.println("Please enter length of a rectangle");

length = Integer.parseInt(br.readLine());

System.out.println("Please enter width of a rectangle");

width = Integer.parseInt(br.readLine());

}

catch(NumberFormatException ne)

{

System.out.println("Invalid value" + ne);

System.exit(0);

}

catch(IOException ioe)

{

System.out.println("IO Error :" + ioe);

System.exit(0);

}

int perimeter = 2 * (length + width);             

System.out.println("Perimeter of a rectangle is " + perimeter);

   }             

}

  Read character from console using Input Stream

import java.io.IOException;

public class ReadCharFromConsoleExample

{

public static void main(String[] args)

{

int iChar = 0;

System.out.println("Read user input character example");

try

{

System.out.println("Enter a character to continue");

iChar = System.in.read();

System.out.println("Char entered was : " + (char)iChar);

}

catch(IOException e)

{

System.out.println("Error while reading : " + e);

     }

   }

}

Java String Buffer append new line

public class JavaStringBufferAppendNewLineExample

{

public static void main(String args[])

{

StringBuffer sbf = new StringBuffer("This is the first line.");

sbf.append(System.getProperty("line.separator"));

sbf.append("This is second line.");

System.out.println(sbf);

    }

}

Calculate Circle Perimeter using Java

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

public class CalculateCirclePerimeterExample

{

public static void main(String[] args)

{

int radius = 0;

System.out.println("Please enter radius of a circle");

try

{

BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

radius = Integer.parseInt(br.readLine());

}

catch(NumberFormatException ne)

{

System.out.println("Invalid radius value" + ne);

System.exit(0);

}

catch(IOException ioe)

{

System.out.println("IO Error :" + ioe);

System.exit(0);

}

double perimeter = 2 * Math.PI * radius;

System.out.println("Perimeter of a circle is " + perimeter);

   }

}

Java Pushback Input Stream

import java.io.ByteArrayInputStream;

import java.io.IOException;

import java.io.PushbackInputStream;

public class JavaPushbackInputStreamExamples

{

public static void main(String[] args)

{

String strExpression = "a = a++ + b;"; byte bytes[] = strExpression.getBytes();ByteArrayInputStream bis = new ByteArrayInputStream(bytes);

PushbackInputStream pis = new PushbackInputStream(bis);

int ch;

try

{

while( (ch = pis.read())!= -1)

{

if(ch == '+')

{

if( (ch = pis.read()) == '+')

{

System.out.print("Plus Plus");

}

else

{

pis.unread(ch);

                                               

System.out.print("+");

}

}

else

{

System.out.print((char)ch);

      }

   }

}

catch(IOException ioe)

{

System.out.println("Exception while reading" + ioe);

      }

  }

}