Question

Examples of specifying tokens Example 1. Keyword Keyword is "if", "else", "for", or Regular expression Example 2. Comparison Comparison is all the operators related with comparison (e.g., <, >, < Regular expression: >) .

Answer 1

(1)Keyword "If" ::-

(a)It is a statement in any programming languages.

(b)It evaluates expression.

(c)If expression result is nonzero, that means it is True.

(d)If expression result is zero, that means it is False.

Syntax of if statement::-

if(expression)

{

//Do something

}

(2)Keyword "else":  

(a)else is also statement, It always comes with if statement.

(b)Whenever if statement is not true then else will get executed.

Syntax of else statement::-

if(expression)

{

//Do something

}

else

{

//do something

}

(3)Keyword "for"::- A for loop is a control structure that allows us to write a loop that needs to execute a specific number of times.

Sytanx::-

for ( start; condition; increment ) {
   statement(s);
}

start::- Need to specify starting point.

condition::- Need to specify expression,which control the the loop.

increment::-Need to specify expression which will increment or decrement the value so that loop should not go in infinite loop.

(4)Regular Expression::-

Regular Expression is a sequence of character which will used for pattern matching from any strings.

How to write regular expression::-

(a)Repeater::- (* , + and { }) all symbols are repeater, which particular character is coming multiple times in pattern then we should use repeater.

(b)The asterisk symbol ( * ) when particular character is coming 0 or multiple times then we should use *

(c)The Plus symbol ( + )when particular character is coming 1 or multiple times then we should use +

(d)Wildcard – ( . ) any character can be used any number of times.

(e)Optional character – ( ? )

(f)The caret ( ^ ) symbol: Start of the string.

(g)The dollar ( $ ) symbol:End of the string.

(5)(a)">" ::- Greater than

Ex::- if (10> 5){

printf("yes")

}

(b)"<" ::-Less than

Ex::- if (5<10){

printf("yes")

}

(c)"<=" ::Less than or equal to

Ex::-

f (10<=10){

printf("yes")

}

(d)">=" ::Greater than or equal to

Ex::-

f (10>=10){

printf("yes")

}