display file size in mb in linux

C++
prashad@ubuntu:~/working_dir/opencv$ ls -lh CMakeLists.txt
-rw-r--r-- 1 prashad prashad 65M Sep 29 01:05 CMakeLists.txt
prashad@ubuntu:~/working_dir/opencv$ 


NOTE:
To display the file sizes in units like 7K, 5M, 8.2G, etc… use the -lh option with  ls. 
"ls -lh"
Source

Also in C++: