Sum of Integers - From File

[Cubba27]

Hey All,

right i've been tasked with writing a program that reads data from a file, consisting of both types String & Int, and then writing that data to another file with the addition of the integers totaled up. I've managed to get the majority of the program working, however i stuck at how to total up the Integers. Below is the input file and the expected output:

Input File:

Exam1 66
Exam2 57
Exam3 40
Exam4 72

Output File:

Exam1 66
Exam2 57
Exam3 40
Exam4 72
Total Marks: 235

Could anyone help me to figure this one out please, i've been at it for a fair few days now. Thanks :)

below is part of current code:

        int total = 0;
	File input = new File("input.txt");
	File output = new File("output.txt");
	Scanner in = new Scanner(input);
      	
    PrintWriter writeOutput = new PrintWriter(output);
    
    	while (in.hasNext())
    	{
      	  String exam = in.next();
      	  int result = in.nextInt();
      	  writeOutput.println(exam+" "+result);
      	}
      	  writeOutput.print("Total: "+total);
      	  writeOutput.close();

[Eranga]

Store all in integers in an arrays, and add up them before write to the second file. Just think about that... you have lots of difficulties. Think about it first.

[gcalvin]

Eranga's suggestion is a good one, but based on the requirements you have stated, an array is not even necessary. Here's what you need to do:

    open a file for reading
    open a file for writing
    initialize sum to 0
    while there is still more to read
        read a line from the first file
        extract the integer from the line
        add the integer to sum
        write the line on the second file
    write your Total Marks line on the second file
    close the second file
    close the first file

Some of those things are easy to do, and others are slightly harder. Your code is not far off, but you are forgetting one simple but crucially important part. Also, have you learned about BufferedReader and BufferedWriter? If so, I would use them for this exercise.

-Gary-

[Eranga]

That's why i told,

Just think about that... you have lots of difficulties.

:p

So he can learn about arrays.

[fceruti]

just change

int result = in.nextInt();

for

total += in.nextInt();

[gcalvin]

just change

int result = in.nextInt();

for

total += in.nextInt();

No. That won't work.

-Gary-

[fceruti]

true you need the result value to print it, so keep that line and add below:

total += result;

that works

[fceruti]

oh and btw, every time you do i/o operations you need to put try/catch statements. Fix that 2 things and you have ur code running

[Cubba27]

total += in.nextInt();

Ah HaHa... thank you all :). I had in fact already used the code above when trying to get it working, but after reading all of your suggestions i got it.... can't believe how close i was :)

STRING allPostersOnThread = "HEROES!!!!!!"; :D