Can you please help me by solving this question? (Operating System course)

Write a C program in which the child process writes to a pipe all processes running in the system, while the parent process reads from the pipe to count only those processes owned by the current logged user. Hint: to get the login username, use the function char * cuserid(char *string); which returns the login name in the variable buf, as long as the name does not exceed size parameter passed to the function.