শেখ এবং শেখাও(Sekho ebang Sekhao)

I will be in Durgapur in Feb, the first three people who can solve & mail the answers to me will get treat from me :)
Solve them using 'C' language only.

1. Reverse a single linked list
2. Find number of occurences of a character in a string
3. Print a given integer on stdout only using putchar