display a random grid for a game in c++

I am a student in first year in computer science and I was asked to code takazu. I wanted to know how to make sure to have a valid random grid in C ++. And if it was possible. Is it then possible to enter lots of grids myself and then make sure that the boxes are deleted randomly.

for the moment I just created a dynamic table, filling in the values ​​myself. but for the game you need several grids

thank you.