Taking C++, need help with a problem pls

[billyusa]

Hello all, im taking a intro to c++ class as part of my design comm, and having issues withthe codelab part (online). First off it doesnt give any help to what you are doing wrong.

the prob is:

Given an int variable n that has been initialized to a positive value and, in addition, int variables k and total that have already been declared, use a while loop to compute the sum of the cubes of the first n counting numbers, and store this value in total . Thus if n equals 4, your code should put 1*1*1 + 2*2*2 + 3*3*3 + 4*4*4 into total . Use no variables other than n , k , and total . Do NOT modify n .

ive attempted this code:


n=0;
k=1;

while( n=0; n >=1; n<=k)
{
total = total + k;
k++;
}


not sure what im doing wrong,.

pls help thanks

[whodgson]

You need to write the algorithm in plain English along the following lines before writing the code.
Assume n has been initialized to some value and k and total have been declared.
initialize k=0 and total=0
The while parameter could be (k<n) // because u don`t know the value of n
if n=4 k would loop through 0,1,2,3
The loop body could be:{ total+=(k+1)*(k +1)*(k+1)
k++}
return total //after loop terminated
if n=3, total would = 1*1*1 + 2*2*2 +3*3*3=36 maybe!
I hope this does not contravene the guidelines

[billyusa]

ok i think im getting it,

k=0
total=0

while (n=4; k < n; k++)
{total=total + (k+1)*(k+1)*(k+ 1)
}

[billyusa]

ok i think im getting it,

k=0
total=0

while (n=4; k < n; k++)
{total=total + (k+1)*(k+1)*(k+ 1)
}

but it doesnt seem to be accepting it, I really dislike codelabs, ratherr then helping you it just sits there, saying ERROR!.

your help is appreciated thanks again

[Simonius]

Your while looks a bit weird, what you put between the () belongs after a for.
The following code should do the trick.
But it isn't exactly like I want to, are you sure they didn't include math so you could use the pow function?

code removed, please offer algorithm as opposed to the answer

Note total+=k*k*k is the same as total = total + k*k*k

[whodgson]

How can you initialize n with 4 if you don`t know the value of n? You want your loop to continue until it is 1 less than n assuming your counter starts at 0.

[Simonius]

You don't need to initialise n, that's already done.

@ts: what you put in your while belongs in a for, you should just loop it while k is less then n because that's basicly what you want.