43) Using Pop (S1,Item),Push(S1, Item), Getlist(Item), Pop(S2,Item), and the variables S1,S2(stacks with Top1 and Top2) and Item and given the input file: A,B,C,D,E,F Which stack are possible?

44) A postfix expression is merely the reverse of the prefix expression

45) Following sequence of operations is performed on a stack push(1),push(2),pop, push(1),push(2)pop,pop,pop,push(2),pop.The sequence of poped out values are

46) In evaluating the arithmetic expression 2*3-(4+5),using stacks to evaluate its equivalent postfix form, which of the following stack configuration is not possible?

47) Stack A has the entries a,b,c(with a on top).
Stack B is empty.An entry popped out of stack A can be printed immediately or pushed to stack B.An entry popped out of the stack B can only be printed. In this arrangement, which of the following permutations of a,b,c are not possible