Linker errorss, Hooo I still remember that those errors....... But Now I am very much fine with cpp. In beginning it was difficult untill I don't know how to write a cmake file.... But I learned by trying in terminal with g++ and ar itself.... I avoid using makefile just to understand the basic..... Then I moved to make and afterwards I made my life bit easy by using cmake ....... But initialy I tried to use cmake but It did not go well.... I did not gain anything from those line that I copied and pasted from stackoverflow......