Thread: incompatible implicit declaration of built-in function

warning: incompatible implicit declaration of built-in function âstrlenâ
warning: undefined reference to `sqrt'
warning: implicit declaration of function âstrcmpâ
warning: implicit declaration of function âstrcatâ
warning: incompatible implicit declaration of built-in function âstrcatâ

I have all the necessary includes, do i need to do some extra command to get this to compile properly?

How do i fix that when my SSH Secure Shell compiles the file, i get a bunch of those..