What is the error in the following codes?

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C++

Code1:

int *pint = nullptr;
pint = new int;
if (pint == nullptr)
*pint = 100;
else
cout << "Memory allocation error\n";

Code 2:
void doSomething(int * const ptr)
{
int localArray[] = { 1, 2, 3 };
ptr = localArray;
}

What I have tried:

code 1:
int *pint = nullptr;
pint = new int;
int x;
if (pint == &x)
*pint = 100;
else
cout << "Memory allocation error\n";


code 2:
void doSomething(int * ptr)
{
int localArray[] = { 1, 2, 3 };
ptr = localArray;
}