Unions:

1: Suppose that s is the following structure

struct shape {
       int shape_kind;
       union
       {
       	     struct
	     {
		int height, width;
	     } rectangle;
	     struct
	     {
		int radius
	     } circle;
	}u;
} s;


Indicate which of the following statements are legal, and show how to
repair the ones that aren't

a.) s.shape_kind = 1;
b.) s.height=25;
c.) s.u.rectangle.width =8;
d.) s.u.circle =5;

Structures:

2:
a.)Using typedef and a struct, declare a type named 
complex, with two members, real and imaginary of type double.







b.) Declare complex variables c1, and c2 with the same values. 
Initialize them in different ways.




c.) Write a function named make_complex that takes two doubles, and
returns a complex with the given parameters


complex make_complex(double real, double imaginary){





}




d.) Write a function named add_complex that takes two complex
 number and adds the corresponding members of its arguments, 
then returns the result.

complex add_complex(complex c1, complex c2){







}


3:Assume that the "time" structure contains three 
members: hours, minutes and seconds. Write a function 
that takes a long representing the time in seconds 
since midnight, and returns a structure centaining the
 equivalent time in hours (0-23), minutes (0-59), and seconds (0-59).

struct time split_time(long total_seconds){






}

Stacks & Queues
4:Write a program that evaluates a string of
parentheses/braces/brackets and returns true if they are properly
balanced. Use a stack struct with standard operations.













5: What happens to queue during this code segment?
Stack stack;
while(! isEmpty(queue)) {
  push(stack, dequeue(queue));
}
while(! isEmpty(stack)) {
  enqueue(queue, pop(stack));
}