1.  Identify which of the following are declarations 

1 : extern int x; 
2 : float square ( float x ) { ... } 
3 : double pow(double, double);

A. 1
B. 2
C. 1 and 3
D. 3

Answer: Option C

Explanation:

extern int x; - is an external variable declaration.

double pow(double, double); - is a function prototype declaration.

Therefore, 1 and 3 are declarations. 2 is definition.