simple c++ practice by using cmake and building with .so

Usage

[USAGE] for hello world:

./app

[USAGE] for both matrix in same size:

./app [size]

[USAGE] for 2 matrix in diffrence size:

./app [m1_size] [m2_size]

[USAGE] for 2 matrix in diffrence row and col, which m1_col should equel to m2_row:

./app  [m1_row] [m1_col] [m2_row] [m2_col]