using memset() in double type array

Question

I want to set all the index value to -1 in a double array.
Here is my code :

double dp[505];
memset(dp,-1,sizeof(dp));
cout<<dp[0]<<"\n";

But it is showing nan when i try to print its value.

What does nan mean? Is it possible to use memset() in double array?

Answer 1

In C++, using header <algorithm>, you can write:

double initValue = -1;
std::fill_n(dp, 505, initValue);

memsetting a double array with a non-double value won't work.