找到两个数的差为一个特定数

Given an integer 'k' and an sorted array A (can consist of both +ve/-ve nos), output 2 integers from A such that a-b=k.

void fun(vector<int> &a, int key)
{
int n = a.size();
if (n <= 1)
{
return;
}

key = abs(key);
int p = 1;
int q = 0;
while (q < p && p < n)
{
if (a[p] - a[q] == key)
{
cout << a[p] << " " << a[q] << endl;
return;
}
else if (a[p] - a[q] > key)
{
q++;
}
else
{
p++;
}
}
}