title: Should convert String to Int in java @ 1.5 or use other method?
body: <p>I'm writing a program in which I want to terminate program by pressing any key(whether character or numbers), so I did a conversion from string to int using <strong>Integer.parseInt(variable)</strong> method and compare choices if it is not desired choice it should terminate the program but it show an error <strong>Exception in thread "main" java.lang.NumberFormatException: for input string: "d"</strong>.</p>
  
  <p>program code is as follows:-</p>
  
  <pre><code>public class mainClass {
      public static void main( String[] ar ) {
          double res = 0;
          Scanner in = new Scanner( System.in );
          Tdata td1 = new Tdata(); // another class object
  
          System.out.println( "****Temperature Conversion****" );
          System.out.println( "------------------------------" );
          System.out.println( "Press 1-&gt; C2F" );
          System.out.println( "Press 2-&gt; F2C" );
          System.out.println( "&lt;- Press aNY kEY TO Exit -&gt;" );
  
          String choice = in.nextLine();
  
          // =======================================================
          int ch = Integer.parseInt( choice );
          System.out.println( "String has converted: " + ch ); 
          // verifying if converted into int
          if( ch == 1 || ch == 2 ) {
              if( ch == 1 ) {
                  td1.getVal( 37.4 );
                  res = td1.C2F();
                  System.out.println( "Resulted Temperature: " + res );
              }
              else if( ch == 2 ) {
                  td1.getVal( 104.2 );
                  res = td1.F2C();
                  System.out.println( "Resulted Temperature: " + res );
              }
              else {
                  System.out.println( "mind your input plz" );
              }
          }
          else {
  
              System.out.println( "&lt;- You select to exit -&gt;" );
              System.exit( 0 );
          }
          // =======================================================
      }// end of main
  }// end of public class
  </code></pre>
  
  <p>Now I think that I should convert undesired input to its previous state ie. String state.. is it right way or should Try another predefined method available in <em>api</em>.</p>
  
  <p>-Thanks!
   Niks</p>