Thread: Exception Errors

I'm taking in an adjacent list and turning it into an adjacent matrix. I can run it without trying to turn input into inputInt.

This is what I have, I know it's sloppy but here:

public class scc {
	public static void main(String[] args) {
 
String fileName=args[0];		//input filename from command line
		String newFile=fileName+".scc";		//create new file with .scc extension
		int size=Integer.parseInt(args[1]);	//number of verticies //THIS IS FINE
 
		int adjMatrix[][] = new int[size][size];
		int i=0;
		String input;
 
		//----Read from file----
		Scanner fromFile=null;
 
		try {           [INDENT][/INDENT]//try and catch
			fromFile=new Scanner(new File(fileName));
		}
 
		catch (FileNotFoundException e) {
			System.err.println("Error opening the file " + fileName);
			System.exit(0);
		} 
		fromFile.useDelimiter(",");
		while(fromFile.hasNextLine()) {
			while(fromFile.hasNext()){ 
				input=fromFile.next();
				int hold=Integer.parseInt(input);  //THIS IS WHERE I GET ISSUES
				adjMatrix[i][hold-1]=1;
			}
			i++;
		}
		fromFile.close();
		i=0;
		//----------------------------------
		System.out.println("\n\n");
		for (i=0;i<50;i++) {
			for(int j=0;j<50;j++){
				System.out.print(adjMatrix[i][j]);
			}
			System.out.println();
		}
 
 
	}
}

However, with inputInt i get the errors:

humer015@humer015-Ubuntu:~/CSCI4041/prog2$ java scc graph.txt 8
Exception in thread "main" java.lang.NumberFormatException: For input string: "2
1
2"
	at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)
	at java.lang.Integer.parseInt(Integer.java:458)
	at java.lang.Integer.parseInt(Integer.java:499)
	at scc.main(scc.java:33)

Any help would be great. Thank you.

hmm... that's weird. The next() method is taking in multiple numbers at a time. What you could do is just use the Scanner.nextInt() method and skip the trouble of having to use the Integer wrapper class to convert from String to int.

int hold = fromFile.nextInt();