Thread: this is fun but Im new and confused

so here is something simple I can not get to work. What going on?
basically I am given an array temps
double temps
n = the number of elements in the array
i want to write a loop to create the average of the figures in the array temps.

I declared two more variables k and temp
here is what I have so far

Code:

for( k=0;k<=n; k++) {
  total++;

aveTemp = temps[total] / n;
  }

Total starts out as some random number (unless you set it to 0 and didn't tell us). You then add 1 to it, n+1 times, so now total is (random number)+n+1. You then try to use that as an array index into temps, which is just so not going to work, and then you divide by n.

okay so lets say i declare total to 0 when I initialize.
Basically I just want to use total as a temp holder to do the reverse.
the way i see it is. I have the for loop that is reversing the data stored in n and stores that in total.
do i need 2 loops then?
all i want to do is get the sum of the N values and then divide by the number of n values right?

so the for loop i have gives me the sum of the n values right? and then i should just divide by N no?
What am I missing

Hey Tabstop I got it. One I declared total to 0 it all clicked. Thanks for pointing that out.
here is what i used

Code:

total = 0;

for (k = 0; k<n; k++) 
 total += temps[k];

avgTemp = total / n;

so now I'm stumped again with another problem. IN this case if to reverse the array.

Code:

for (k=n-1; k>=n;k--) {
    temp = a[k];
    a[n] = temp;
  }

This is what i have thus far. So I have an array a and n is the number of elements in array a
so
a[n]

so what i tried to do here was reverse the order of the elements in n and assign them to temp. i feel like another step is needed but im not sure what it is? Any help much appreciated thanks

Swapping two elements (which is what you need to do) requires three = signs.

Also, your conditions on the for-loop are all over the place.

really what wrog with the for loop? I thought that was the part that was correct? I reeally dont see a problem. it just reverse the elements of N?

Well, it will never happen, is what's wrong with it. You set k to be n-1, but the loop will only continue while k is bigger than n.

i dont know
this is what i am doing now .still not getting it.

Code:

for (k=n-1; k>=n;--k){
 temp = k;
 k = n;
 a[n] = k;
}

I want the loop seems to be written for what i want. It should start a the end of the elements of N and work its way down to just above N. When it become less then N it should stop

Let's walk through this for a minute, and let's suppose n is 10.
1. Set k = n-1 --> k = 9
2. While k >= 10
some stuff
3. Decrease k by 1
How many times do you think this is going to loop?

Once we get this straight, we'll look at what's going on inside the for loop.

i see what you mean
so then how about this

Code:

 for(k=a[n] -1; k>=n; k--)

in this case now k is = to the last in the array rather then just a variale n
right?

I don't know why you are so morally opposed to

Code:

for (first = 0 ...

since that's where you have to start.

I guess i dont get it. From my thinking I have to start at the last of the elements of n and work in reverse order. So starting at 0 would be starting at the first element of N not the last.
Its the concept of the array that is confusing me

If you think you can reverse an array (in place, not copying to a different array) without working both ends against the middle, you're crazy. When you put the last entry in the 0 slot, you're also going to have put the 0 entry in the last slot.

Actually I dont think anything. I am learning this as I do it so I have no idea what you can and can not do.