CMake turtorial sample code
#exp2 write your own hello lib
compile: $cd ~/code/exp2/src $cmake . $make
usage: $./hello
#exp3 use libPNG in CMake, and buile subdirectory pre-install $sudo apt-get install libpng-dev libzip
compile: $cd ~/code/exp3/build $cmake .. $make
usage: under path ~/code/exp3 $./pngsample france.png italy.png
#exp4 qt window example $cd ~/code/exp4 $cmake . $make
usage: ./qthelloworld
ref: https://drakeguan.org/blog/2008/03/ba-wan-CMake-de-di-yi-bu/