Simple Lexer/Scanner for Java programming language.
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Go to the directory and use the following commands.
javac Lexer.java java Lexer
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"source.txt" contains the source code to be scanned.
// Binary Search in Java
import java.util.*;
class BinarySearch {
public static void binarySearch(int arr[], int first, int last, int key) {
int mid = (first + last) / 2;
while (first <= last) {
if (arr[mid] < key) {
first = mid + 1;
} else if (arr[mid] == key) {
System.out.println("Element is found at index: " + mid);
break;
} else {
last = mid - 1;
}
mid = (first + last) / 2;
}
if (first > last) {
System.out.println("Element is not found!");
}
}
public static void main(String args[]) {
int arr[] = {
10,
20,
30,
40,
50
};
int key = 30;
int last = arr.length - 1;
binarySearch(arr, 0, last, key);
}
}Lexemes Tokens
// Binary Search in Java SINGLE_LINE_COMMENT
import KEYWORD (import)
java IDENTIFIER
. FULL_STOP
util IDENTIFIER
. FULL_STOP
* ARITHEMATIC_MULT
; SEMICOLON
class KEYWORD (class)
BinarySearch IDENTIFIER
{ LEFT_BRACES
public KEYWORD (public)
static KEYWORD (static)
void KEYWORD (void)
binarySearch IDENTIFIER
( LEFT_PAREN
int KEYWORD (int)
arr IDENTIFIER
[ LEFT_BRACKET
] RIGHT_BRACKET
, COMMA
int KEYWORD (int)
first IDENTIFIER
, COMMA
int KEYWORD (int)
last IDENTIFIER
, COMMA
int KEYWORD (int)
key IDENTIFIER
) RIGHT_PAREN
{ LEFT_BRACES
int KEYWORD (int)
mid IDENTIFIER
= ASSIGNMENT_OP
( LEFT_PAREN
first IDENTIFIER
+ ARITHEMATIC_PLUS
last IDENTIFIER
) RIGHT_PAREN
/ ARITHEMATIC_DIVISION
2 INT_LITERAL
; SEMICOLON
while KEYWORD (while)
( LEFT_PAREN
first IDENTIFIER
<= RELATIONAL_LE
last IDENTIFIER
) RIGHT_PAREN
{ LEFT_BRACES
if KEYWORD (if)
( LEFT_PAREN
arr IDENTIFIER
[ LEFT_BRACKET
mid IDENTIFIER
] RIGHT_BRACKET
< RELATIONAL_LT
key IDENTIFIER
) RIGHT_PAREN
{ LEFT_BRACES
first IDENTIFIER
= ASSIGNMENT_OP
mid IDENTIFIER
+ ARITHEMATIC_PLUS
1 INT_LITERAL
; SEMICOLON
} RIGHT_BRACES
else KEYWORD (else)
if KEYWORD (if)
( LEFT_PAREN
arr IDENTIFIER
[ LEFT_BRACKET
mid IDENTIFIER
] RIGHT_BRACKET
== RELATIONAL_EQUAL
key IDENTIFIER
) RIGHT_PAREN
{ LEFT_BRACES
System IDENTIFIER
. FULL_STOP
out IDENTIFIER
. FULL_STOP
println IDENTIFIER
( LEFT_PAREN
"Element is found at index: " STRING_LITERAL
+ ARITHEMATIC_PLUS
mid IDENTIFIER
) RIGHT_PAREN
; SEMICOLON
break KEYWORD (break)
; SEMICOLON
} RIGHT_BRACES
else KEYWORD (else)
{ LEFT_BRACES
last IDENTIFIER
= ASSIGNMENT_OP
mid IDENTIFIER
- ARITHEMATIC_MINUS
1 INT_LITERAL
; SEMICOLON
} RIGHT_BRACES
mid IDENTIFIER
= ASSIGNMENT_OP
( LEFT_PAREN
first IDENTIFIER
+ ARITHEMATIC_PLUS
last IDENTIFIER
) RIGHT_PAREN
/ ARITHEMATIC_DIVISION
2 INT_LITERAL
; SEMICOLON
} RIGHT_BRACES
if KEYWORD (if)
( LEFT_PAREN
first IDENTIFIER
> RELATIONAL_GT
last IDENTIFIER
) RIGHT_PAREN
{ LEFT_BRACES
System IDENTIFIER
. FULL_STOP
out IDENTIFIER
. FULL_STOP
println IDENTIFIER
( LEFT_PAREN
"Element is not found!" STRING_LITERAL
) RIGHT_PAREN
; SEMICOLON
} RIGHT_BRACES
} RIGHT_BRACES
public KEYWORD (public)
static KEYWORD (static)
void KEYWORD (void)
main IDENTIFIER
( LEFT_PAREN
String IDENTIFIER
args IDENTIFIER
[ LEFT_BRACKET
] RIGHT_BRACKET
) RIGHT_PAREN
{ LEFT_BRACES
int KEYWORD (int)
arr IDENTIFIER
[ LEFT_BRACKET
] RIGHT_BRACKET
= ASSIGNMENT_OP
{ LEFT_BRACES
10 INT_LITERAL
, COMMA
20 INT_LITERAL
, COMMA
30 INT_LITERAL
, COMMA
40 INT_LITERAL
, COMMA
50 INT_LITERAL
} RIGHT_BRACES
; SEMICOLON
int KEYWORD (int)
key IDENTIFIER
= ASSIGNMENT_OP
30 INT_LITERAL
; SEMICOLON
int KEYWORD (int)
last IDENTIFIER
= ASSIGNMENT_OP
arr IDENTIFIER
. FULL_STOP
length IDENTIFIER
- ARITHEMATIC_MINUS
1 INT_LITERAL
; SEMICOLON
binarySearch IDENTIFIER
( LEFT_PAREN
arr IDENTIFIER
, COMMA
0 INT_LITERAL
, COMMA
last IDENTIFIER
, COMMA
key IDENTIFIER
) RIGHT_PAREN
; SEMICOLON
} RIGHT_BRACES
} RIGHT_BRACES