数组打印出垃圾值

Question

I have an excercise were I have to write a recursion function that calculates e^x using a formula. I managed to do that, but the exercise says that I have to store the results in an array, this is where I hit the wall, this is my code:

double exp (double x, int n, int* fakt, double* xpot) {

static double result;
static int i;
static double *A;
A  = (double *) malloc(n * sizeof(double));

if (i == n)
{
    for(int k = 0; k < n; k++)
        cout << A[k]; //this prints out garbage values
    return result;
}


if (i != 0 || i != 1)
{
    for (int j = 1; j <= i; j++)
    *fakt = *fakt * j;


}
*xpot = pow(x, i);


result += *xpot / (double)*fakt;
A[i] = result;

*fakt = 1;

i++;

return exp(x, n, fakt, xpot);

}

I would pass the array as the function argument, but the task specifically says that:

double exp (double x, int n, int *fakt, double *xpot);

is the prototype. My question is why the loop prints out garbage values, and is there a way to fix it?

Answer 1

You do not initialize the values of A thats why there is garbage printed.

Also:

• if (i != 0 || i != 1) is equal to if (true) .
• Each call to your exp function will leak a good amount of memory... A is never free d
• xpot and fakt might be nullptr , what could go wrong?