Convert values in loop to correct data types

Question

I need to convert the values in a loop to the correct data types. It compiles, but I get an error. It says,
Exception in thread "main" java.lang.NumberFormat Excepton: A
at java.lang.Integer.parseInt(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at ExtFile.main(ExtFile.java:22)
Here is the code:
import java.text.* ;
import java.io.* ;
class ExtFile
public static void main (String args[]) throws IOException
// Open the external file whose file name was provided as a
// command line program invocation argument.
ExternalFile dataFile = new ExternalFile(args[0]);
String dataLine = dataFile.getLine();
char candidate;
int curPrecinct;
String precinctIn;
while (!dataFile.havehitEOF())
precinctIn = dataFile.getLine();
candidate = dataLine.charAt(0);
curPrecinct = Integer.parseInt(dataFile.getLine());
// Get data line to process
dataLine = dataFile.getLine();
System.out.println(dataLine);
} // EndWhile
// Close the data file
dataFile.close();
} // EndMain
} // Endclass ExtFile
What does this exception mean and how might I fix it??

Answer 1

Hello,
The line of code:
curPrecinct = Integer.parseInt(dataFile.getLine());accepts a String (stored in a file) and produces an int (an integer representation of the String). However, if you pass it a String which doesn't represent a integer an exception is thrown. For example, if you want to obtain an integer from the String "123a", an exception will arise because you can not parse "123a" into an int because 123a is not an int, that is, it has a letter 'a' in it - and ints do not.
To correct this you must pass (make the line in the file) represent an int.
I hope this works.