GATE 2017 CS – Question 53

Consider the following grammar:

stmt   -> if expr then expr else expr; stmt | ò
expr   -> term relop term | term
term   -> id | number
id     -> a | b | c
number -> [0-9]

where `relop` is a relational operator (e.g., <, >, ...), ò refers to the empty statement, and `if`, `then`, `else` are terminals.

Consider a program $P$ following the above grammar containing ten `if` terminals. The number of control flow paths in $P$ is ________. For example, the program

if e1 then e2 else e3

has 2 control flow paths, $e_1 \rightarrow e_2$ and $e_1 \rightarrow e_3$.