Consider the queues Q₁ containing four elements and Q₂ containing none (shown as the Initial State in the figure). The only operations allowed on these two queues are Enqueue (Q, element) and Dequeue (Q). The minimum number of Enqueue operations on Q₁ required to place the elements of Q₁ in Q₂ in reverse order (shown as the Final State in the figure) without using any additional storage is ______________.

Suppose a stack implementation supports an instruction REVERSE, which reverses the order of elements on the stack, in addition to the PUSH and POP instructions. Which one of the following statements is TRUE with respect to this modified stack?

Suppose a circular queue of capacity (n – 1) elements is implemented with an array of n elements. Assume that the insertion and deletion operations are carried out using REAR and FRONT as array index variables, respectively. Initially, REAR = FRONT = 0. The conditions to detect queue full and queue empty are

Consider the following C program:

#include 
#define EOF -1 
     void push (int); /* push the argument on the stack */ 
     int pop (void); /* pop the top of the stack */ 
     void flagError (); 
     int main () { 
       int c, m, n, r; 
       while ((c = getchar ()) != EOF) { 
         if (isdigit (c) ) 
           push (c); 
         else if ((c == '+') || (c == '*')) { 
           m = pop (); 
           n = pop (); 
           r = (c == '+') ? n + m : n*m; 
           push (r); 
         } else if (c != ' ') 
           flagError (); 
       } 
       printf("% c", pop ()); 
    } 

What is the output of the program for the following input ? 5 2 * 3 3 2 + * +