Finding maximum..

I have a text file that looks like this:

400 430 560
305 250 700
800 920 350
670 800 960

It's sorted into three arrays, each column is an array.
But I have to find the largest number, and this needs to be done by row. I'm confused :S

I know by using this code I can find the largest in one array:

Code:

---

        int largeIndex = 0;
               
                for(int i = 0; i < a1.length; i++){
                        if(a1[i] > a1[largeIndex]){
                                largeIndex = i;
                        }
                }

---

But then how do I change it so it goes through each number in each row?

:confused:

Are you trying to find the largest number (display 1 value) or the largest number in each row (display 4 numbers)?

Just 1 value. The largest number in any row

In that case you will need nested loops. Outer loop for rows, inner loop for columns. Compare each value with largest so far.

I thought about doing that, but wouldn't that only work for multi-dimensional arrays? Because in this case I have 3 1d arrays...
I apologize for my noobness haha

Then use one loop for each array and carry the results forward from each loop.

Yeah, I was thinking of finding the max in each array and then comparing to see which is largest...something along those lines

That's one approach. That approach will get harder if you increase the number of arrays to search.
Another is to find the largest so far, carrying forward its value for each loop.

Okay, thanks, I'll try that and see how it works out. :)

Code:

---

method one {
    declare max
    loop number of rows {
        value = method two(current row)
        if value is greater than max {
            change max
        }
    }
    display max
}

---

Then method two simply finds and returns max of a 1d array.

Why don't you use 1 array for all the lines?
Then use a simple code as:

Code:

---

int big = arr[0];
for(int i=0;i<arr.length;i++)
      if(arr[i]>big)
            big = arr[i];

---

Doing int big = 0; is wrong! sinec your biggest number might be negative.

I would have used 1 array, but the instructions on the assignment say the program should read the data from the file into 3 separate arrays. :/

Gah!

I was working under the assumption that you had a 2D array. Neverless the pseudocode posted above would still work with some minor tweaking.

lol this is so stupid,
then just do as I did but to each line which means 3 damn loops :0
So for that you need 4 variables, bigAr1, bigAr2, bigAr3 and bigAr4.
After finding the biggest number in each line you will have to make tones of if's conditions to find the largest one between those 4.

hahaha yeah that's pretty much what I was going for. thanks

Quote:

---

Originally Posted by tnrh1

lol this is so stupid,
then just do as I did but to each line which means 3 damn loops :0
So for that you need 4 variables, bigAr1, bigAr2, bigAr3 and bigAr4.
After finding the biggest number in each line you will have to make tones of if's conditions to find the largest one between those 4.

---

What a load of tosh. You only need one for loop and you only need one variable.

Quote:

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Originally Posted by Junky

What a load of tosh. You only need one for loop and you only need one variable.

---

Show me the a shorter solution if the arrays lengths are diffrent.

In case the arrays lengths is the same, here is a better solution I worked on now:

Code:

---

int biggest = ar1[0];
for (int k=0;k<ar1.length;k++)
{
        if(ar1[k]>biggest)
                biggest = ar1[k];
        if(ar2[k]>biggest)
                biggest = ar2[k];
        if(ar3[k]>biggest)
                biggest = ar3[k];
        if(ar4[k]>biggest)
                biggest = ar4[k];           
}

---

Code:

---

class Foo {
    declare max
    declare arr1
    declare arr2
    declare arr3
    declare arr4

    public void stuff() {
        //fill arrays
        findMax(arr1);
        findMax(arr2);
        findMax(arr3);
        findMax(arr4);
        display max
    }

    private void findMax(arr) {
        loop arr {
            if current value is greater than max
                change max
            }
        }
    }
}

---

One loop and one variable (excluding the four arrays).

Quote:

---

loop arr {

---

How can you run a loop on 4 arrays if the length of them is diffrent?Looking at your post number makes me think twice that I'm wrong but I still can't find an asnwer to that <<<<<<<

Do you see how in the stuff method I call the findMax method 4 times, once with each array?