Recursive Fibinocci Sequence in C

gistfile1.h

void doWork(int a1,int a2,int n)                                                
{                                                                               
   int a3 = 0;                                                                 
                                                                                                                                  
   if(n <= 2)                                                                  
   {                                                                           
      return;                                                                 
   }                                                                           
   else                                                                        
   {                                                                           
      a3=a1+a2;                                                               
      doWork(a2,a3,n-1);                                                      
   }                                                                           
}