### I Don't Know What to Write for the Title, HELP!!

So i'm doing this:

"Write a program that asks the user to type an integer N and compute u(N) defined with :
u(0)=3
u(n+1)=3*u(n)+4"

from: http://en.wikibooks.org/wiki/C++_Programming/Exercises/Iterations#EXERCISE_7

I know there is solutions for this, but i'm trying to make mine. Its exercise.

Theeeeenn....this is my attempt:

 ``1234567891011121314151617181920212223242526`` `````` #include using namespace std; int main() { int a[0]=3; for(int n=0; n<9; n++) { cout << "Please insert a number to calculate a[" << n <<"]: "; cin >> a[n]; cout << endl; if(n==0) { cout << a[0] << endl; } else { a[n] = 3*a[n-1]+4; cout << a[n] << endl; } } return 0; }``````

but, unfortunately, its always error at line 6. Did i declare it the wrong way?
Last edited on
At line 6 you are declaring an array with 0 elements and assigning 3 to it.That part is wrong.
The general syntax for declaring an array is-
 ``12`` ``````int a[5] = {2,1,3,5,4}; int b[5] = { 0 }; //initialise all to 0 ``````

Please refer to the c++ tutorial at this site or your book.
And your implementation looks a little quirky .here's a hint .create a function "int u(int n)" and if the valve of n is equal to 0 return 0 else return 3*u(n-1)+4
Last edited on
You should use a function instead of the array that is used by you incorrectly.
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