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+9 votes

In the following Pascal program segment, what is the value of X after the execution of the program segment?

X := -10; Y := 20;
If X > Y then if X < 0 then X := abs(X) else X := 2*X;
  1. $10$
  2. $-20$
  3. $-10$
  4. None
asked in Algorithms by Veteran (59.6k points)
edited by | 609 views

1 Answer

+21 votes
Best answer

Answer of $X$ remains unchanged. As the if condition becomes false.

X := -10

Answer is C . This is classic example of $if-else$ issue. Always $else$ matches for nesting to the closest $if$  in $C$ Programming & Pascal .

if (x>y)
   if (x<0)
answered by Boss (43k points)
edited by
else matches to closest if in all languages?
For sure in C & Pascal ! We don't get any other languages in GATE !
But here x < y i.e.  -10 < 20
Yes you seem correct. Updated.
When having confusion, always try to match else with last unmatched if condition.

This is usually the solution the compiler follows for dangling else problem during compilation of a program.

Reference: Ullman for compilers

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