Someone help me in loop of C++

I am not able to understand and if understand then not able to write them according to the program I am given to create. this loop is the hardest thing in cpp i have studied untill now. I know the whole film is left amd there is lot to learn in C++ but still ... : (

Someone give me a resource good one to learn loops concept or help by eplaining or helping in creating programs small or by anyways i will appreciate a lot.