The main() function is always

The purpose of the following program fragment,

b = s+b;

s=b-s;

b=b-s; where s, b are two integers, is to:

Which of the following about conditional compilations is not true?

1: It is taken care of by the computer.

2: It is setting the compiler option conditionally.

3: It is compiling a program based on a condition.

4: It is taken care of by the pre-processor.

For C preprocessor, which of the following is/are true?

1: Takes care of conditional compilation

2: Takes care of macros

3: Takes care of included files

4: Act before compilation

An implementation of a queue Q, using two stacks S$1$ and S$2$is given below

void insert (Q, x) {
push (S$1$, x);
}
void delete (Q) {
if(stack-empty (S$2$)) then
if(stack-empty(S$1$)) then {
print ("Q is empty");
return;
}
else while(! (stack-empty (S$1$))) {
x=pop(S$1$);
push (S$2$, x);
}
x=pop(S$2$);
}
Let n insert and m($\le$n) delete operations be performed in an arbitrary order on an empty queue Q. Let x and y be the number of push and pop operations performed respectively in the process. Which one of the following is true for all m and n?