linux count files in subdirectories

C++
find DIR_NAME -type f | wc -l
ls | wc -lfind . -maxdepth 1 -type d | while read -r dir
do printf "%s:\t" "$dir"; find "$dir" -type f | wc -l; done
find . -type f | cut -d/ -f2 | sort | uniq -c | sort -nrdu -a | cut -d/ -f2 | sort | uniq -c | sort -nr

Source

Also in C++: