Lauguage : C++
I have to make function 'add' overloaded.
'add' function has array a[] as parameter.
I wrote my code but it doesn't work.
There is no error or caution but it doesn't start.
What is the problem on my code?
int add(int a[], int n, int b[])
{
int sum = 0;
for (int i = 0; i < n; i++)
sum += (a[i] + b[i]);
return sum;
}
int add(int a[], int n=5)
{
return add(a, n, NULL);
}
sum += (a[i] + b[i]);
indexes b, which can be NULL. That's Undefined Behavior.
A good way to avoid that pitfall is to use std::vector.
When you declare arguments like array in the way you do (e.g. int a[]) then the compiler actually declares the argument to be a pointer.
And in the three-argument overload of the add function the third argument (b) could be a null pointer which you don't check for. Attempting to dereference a null pointer leads to undefined behavior and a probable crash.
Don't access b if it's a null pointer.
int add(int* a, int n, int* b)
{
int sum = 0;
for (int i = 0; i < n; i++)
{
if (b == nullptr)
sum += a[i];
else
sum += a[i] + b[i];
}
return sum;
}
if (b == nullptr) check in the function.int add(int a[], int n, int b[]) { if (b == nullptr) for (int i = 0; i < n; i++) b[i] = 0; int sum = 0; for (int i = 0; i < n; i++) sum += (a[i] + b[i]); return sum; }b[i] = 0; is an error. Thanks to your modified code, now the program work properly. I really really appreciate your help. Maybe I have to study harder.
a[]is an array parameter? That is misleading, because it really is a pointer. Arrays aren't pointers and it is good to understand that early on.NULLdoes? Hint: it's not an array of zeroes.