Arrays are a sequential set of identically-sized chunks of memory. They may also have a section that saves the size of the array (depending on language. Java has Array.length, C has nothing so you have to count). The actual implementation of arrays in memory is (or should be) beyond the scope of an introductory programming course (and matters mainly in lower level languages like C, when you're doing direct manipulation of things in memory... which is well beyond introductory programming!). The size of an array is set on creation and is fixed. It cannot be changed, so know how much you need when you create it... or have logic to move things to a bigger one if needed (in Java, check the Arrays class for array utility methods like that... or just use an ArrayList, though I don't know if you've gone over data structures like the Collections classes).
The simplest way to process an array is to just iterate every element. If your language supports for loops, use them (they're basically the loop of choice for iteration). Pseudocode for array processing:
int i=0;
while(i<array length) {
do stuff
i++;
}
If you actually mean searching... well that's a far more complicated question. Presumably the array elements are ordered. If not you need to first sort (I'm not going into sort optimization. Find an implementation of quicksort or mergesort, or just write bubblesort since you aren't working with anything large). Once sorted, your common searches can be run via binary searching - start in the middle, if the element there is larger than your target you check the lower half, else the upper. Repeat until you find the exact item.
PrintWriter... if this is the Java class you're in luck since that's the language I work with most. It supports output to both files and output streams (the main output streams are System.out and System.error)... but usually you use System.out.print(); to write to standard out. For file output I normally use FileWriter (wrapping in BufferedWriter for the utility methods it provides).
In short, a Java Writer class is used to send characters to an output stream. They support sending multiple data types (int, byte, and chars and arrays of them, as well as String), and provide methods to flush the stream (which causes it to actually write the characters) and close it safely (which involves among other things, flushing it). Essentially, they're the usual class for text outputs (check the API for method signatures and descriptions: http://docs.oracle.com/javase/7/docs/api/java/io/Writer.html - note this is for Java 7, while I think it's the same as 6 here it might differ).
If you want to write text to a file, the normal syntax would be:
PrintWriter writer = new PrintWriter(new File(path));
writer.write(something);
...
writer.close();
To write everything in an array to a file in Java:
PrintWriter writer = new PrintWriter(new File(path));
for(int i=0;i<arrayname.length;i++) {
writer.write(arrayname[i]);
//writer.write("\n"); if you want a new line - I use BufferedWriter for its newLine() method
}
writer.close();
Note that once you call writer.close(), you cannot use that writer to write AT ALL anymore. Trying to do so will throw an exception. Opening a new writer to a file will overwrite the file (in general - FileWriter can be set up to append instead), so you don't want to call close until you're 100% done.
To make the values in an array spit back to screen just use System.out.println(arrayname[i]);
Almost every major language uses the syntax arrayname[x] to reference array elements, and standard programming courses tend to start with Hello World, which should tell you how to write stuff back out to the screen... if you didn't cover Hello World look it up for the language you're using (it's just the standard first exercise when learning a new language).
This took a little bit to regurgitate - it's been a while since I actually cared about how arrays worked exactly (I more often use lists). Feel free to fire off more questions... though I don't know that I'll be able to get back to them in time for your final. That said, I'm sure there's other programmers on the board (though activity isn't what it once was...).
yo i didnt actually think i'd get a legit response! thanks man this helped.
hope i dont fail. we're only learning very simple core basics with 1 dimensional arrays. I believe that on my final, the teacher told us that she will have us read a file that she premade for us with a list of integers listed on its own line, which we will hafto use printwriter to read the file and then take out those integers and put them into an int array and find a specific integer in the array by using some type of loop to find the specific int in a specific element, then output the results and then copy the array into our own txt file with printwriter... i'm not sure how the syntax will work out in this. I dont htink the teacher cares about format (probably the reason why she hasnt taught us anything about the buffered writer).
and this a 2 sided "study guide" she gave out as an example program, this may explain a few things of what we're learning, half my class doesnt know whats going on so asking my classmates to make sense of the program was no very effective:
[SPOILER-BOX]https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-xpf1/v/t34.0-12/10462673_1444788509112025_4438834112775606812_n.jp g?oh=acfb767ec650bcd5c353541105e55db2&oe=539CD579&__gda__=1402788594_49987650010b48991f7ed972520d3d0 a
https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-xpf1/v/t34.0-12/10343509_1444788725778670_6302209647532174993_n.jp g?oh=87ed52813859d777fd9deb3ebcc54968&oe=539C5E7B&__gda__=1402774896_1b934ba05e9a6cac8e318a5e271bdb9 8[/SPOILER-BOX]