Program to implement ASCII lookup table
Last Updated :
08 Feb, 2024
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ASCII stands for American Standard Code for Information Interchange. Computers can only understand numbers, so an ASCII code is the numerical representation of a character such as ‘a’ or ‘@’ or an action of some sort. ASCII lookup table is a tabular representation of corresponding values associated to a character i.e. we can lookup the corresponding octal, decimal, hexadecimal or HTML ASCII of a character.
Here, we are implementing an ASCII lookup table which takes a character as an input and returns the equivalent octal, decimal, hexadecimal and HTML ASCII value for the character. This ASCII lookup table works for alphabets, digits, operators, separators and special symbols.
Example:
Input character = @
Output :
Octal value: 100
Decimal value: 64
Hexadecimal value: 40
HTML value: @
- Step 1: Convert given character into it's equivalent ASCII in decimal form. This can be done by implicitly typecasting the character into an integral value(or subtracting by null).
- Step 2: The value computed in step 1 becomes the decimal representation of the character. Convert the decimal value in octal and hexadecimal forms to obtain the ASCII of the input character into the given formats.
- Step 3: Add characters &# as prefix and ; as postfix of the decimal ASCII, the expression obtained becomes the HTML ASCII of the given character. This way we can easily implement the ASCII lookup table. Follow the code below to see the implementation.
Implementation:
// C++ implementation of ASCII lookup table
#include <iostream>
#include <string>
using namespace std;
// Function to convert decimal value to
// equivalent octal value
int Octal(int decimal)
{
int octal = 0;
string temp = "";
while (decimal > 0) {
int remainder = decimal % 8;
temp = to_string(remainder) + temp;
decimal /= 8;
}
for (int i = 0; i < temp.length(); i++)
octal = (octal * 10) + (temp[i] - '0');
return octal;
}
// Function to convert decimal value to
// equivalent hexadecimal value
string Hexadecimal(int decimal)
{
string hex = "";
while (decimal > 0) {
int remainder = decimal % 16;
if (remainder >= 0 && remainder <= 9)
hex = to_string(remainder) + hex;
else
hex = (char)('A' + remainder % 10) + hex;
decimal /= 16;
}
return hex;
}
// Function to convert decimal value to
// equivalent HTML value
string HTML(int decimal)
{
string html = to_string(decimal);
html = "&#" + html + ";";
return html;
}
// ASCII lookup table
void ASCIIlookuptable(char ch)
{
// Implicit typecasting converts the
// character into it's equivalent ASCII
int decimal = ch;
cout << "Octal value: " << Octal(decimal) << endl;
cout << "Decimal value: " << decimal << endl;
cout << "Hexadecimal value: " << Hexadecimal(decimal) << endl;
cout << "HTML value: " << HTML(decimal);
}
// Driver function
int main()
{
char ch = '@';
ASCIIlookuptable(ch);
return 0;
}
// C++ implementation of ASCII lookup tableusing namespace std;// Function to convert decimal value to// equivalent octal valueint Octal(int decimal){ int octal = 0; string temp = ""; while (decimal > 0) { int remainder = decimal % 8; temp = to_string(remainder) + temp; decimal /= 8; } for (int i = 0; i < temp.length(); i++) octal = (octal * 10) + (temp[i] - '0'); return octal;}// Function to convert decimal value to// equivalent hexadecimal valuestring Hexadecimal(int decimal){ string hex = ""; while (decimal > 0) { int remainder = decimal % 16; if (remainder >= 0 && remainder <= 9) hex = to_string(remainder) + hex; else hex = (char)('A' + remainder % 10) + hex; decimal /= 16; } return hex;}// Function to convert decimal value to// equivalent HTML valuestring HTML(int decimal){ string html = to_string(decimal); html = "&#" + html + ";"; return html;}// ASCII lookup tablevoid ASCIIlookuptable(char ch){ // Implicit typecasting converts the // character into it's equivalent ASCII int decimal = ch; cout << "Octal value: " << Octal(decimal) << endl; cout << "Decimal value: " << decimal << endl; cout << "Hexadecimal value: " << Hexadecimal(decimal) << endl; cout << "HTML value: " << HTML(decimal);}// Driver functionint main(){ char ch = '@'; ASCIIlookuptable(ch); return 0;}// Java implementation for ASCII table lookup
import java.util.*;
import java.lang.*;
class GeeksforGeeks {
// Function to convert decimal value to
// equivalent octal value
static int Octal(int decimal)
{
int octal = 0;
String temp = "";
while (decimal > 0) {
int remainder = decimal % 8;
temp = remainder + temp;
decimal /= 8;
}
for (int i = 0; i < temp.length(); i++)
octal = (octal * 10) + (temp.charAt(i) - '0');
return octal;
}
// Function to convert decimal value to
// equivalent hexadecimal value
static String Hexadecimal(int decimal)
{
String hex = "";
while (decimal > 0) {
int remainder = decimal % 16;
if (remainder >= 0 && remainder <= 9)
hex = remainder + hex;
else
hex = (char)('A' + remainder % 10) + hex;
decimal /= 16;
}
return hex;
}
// Function to convert decimal value to
// equivalent HTML value
static String HTML(int decimal)
{
String html = "";
html = html + decimal;
html = "&#" + html + ";";
return html;
}
// ASCII lookup table
static void ASCIIlookuptable(char ch)
{
// Implicit typecasting converts the
// character into it's equivalent ASCII
int decimal = ch;
System.out.println("Octal value: " + Octal(decimal));
System.out.println("Decimal value: " + decimal);
System.out.println("Hexadecimal value: " + Hexadecimal(decimal));
System.out.println("HTML value: " + HTML(decimal));
}
// driver function
public static void main(String args[])
{
char ch = '@';
ASCIIlookuptable(ch);
}
}
# Function to convert decimal value to equivalent octal value
def Octal(decimal):
octal = 0
temp = ""
while decimal > 0:
remainder = decimal % 8
temp = str(remainder) + temp
decimal //= 8
for i in range(len(temp)):
octal = (octal * 10) + int(temp[i])
return octal
# Function to convert decimal value to equivalent hexadecimal value
def Hexadecimal(decimal):
hex = ""
while decimal > 0:
remainder = decimal % 16
if remainder >= 0 and remainder <= 9:
hex = str(remainder) + hex
else:
hex = chr(ord('A') + remainder % 10) + hex
decimal //= 16
return hex
# Function to convert decimal value to equivalent HTML value
def HTML(decimal):
html = str(decimal)
html = "&#" + html + ";"
return html
# ASCII lookup table
def ASCIIlookuptable(ch):
# Implicit typecasting converts the character into its equivalent ASCII
decimal = ord(ch)
print("Octal value: ", Octal(decimal))
print("Decimal value: ", decimal)
print("Hexadecimal value: ", Hexadecimal(decimal))
print("HTML value: ", HTML(decimal))
# Driver function
def main():
ch = '@'
ASCIIlookuptable(ch)
if __name__ == '__main__':
main()
// C# implementation for ASCII
// table lookup
using System;
class GeeksforGeeks {
// Function to convert decimal value to
// equivalent octal value
static int Octal(int decima)
{
int octal = 0;
String temp = "";
while (decima > 0)
{
int remainder = decima % 8;
temp = remainder + temp;
decima /= 8;
}
for (int i = 0; i < temp.Length; i++)
octal = (octal * 10) +
(temp[i] - '0');
return octal;
}
// Function to convert decimal value
// to equivalent hexadecimal value
static String Hexadecimal(int decima)
{
String hex = "";
while (decima > 0)
{
int remainder = decima % 16;
if (remainder >= 0 &&
remainder <= 9)
hex = remainder + hex;
else
hex = (char)('A' + remainder %
10) + hex;
decima /= 16;
}
return hex;
}
// Function to convert decimal
// value to equivalent HTML value
static String HTML(int decima)
{
String html = "";
html = html + decima;
html = "&#" + html + ";";
return html;
}
// ASCII lookup table
static void ASCIIlookuptable(char ch)
{
// Implicit typecasting converts the
// character into it's equivalent ASCII
int decima = ch;
Console.WriteLine("Octal value: " +
Octal(decima));
Console.WriteLine("Decimal value: " +
decima);
Console.WriteLine("Hexadecimal value: " +
Hexadecimal(decima));
Console.Write("HTML value: " +
HTML(decima));
}
// Driver Code
public static void Main()
{
char ch = '@';
ASCIIlookuptable(ch);
}
}
// This code is contributed by nitin mittal.
// JavaScript code implementation
// JavaScript implementation of ASCII lookup table
function Octal(decimal) {
let octal = 0;
let temp = "";
while (decimal > 0) {
let remainder = decimal % 8;
temp = remainder.toString() + temp;
decimal = Math.floor(decimal / 8);
}
for (let i = 0; i < temp.length; i++)
octal = octal * 10 + Number(temp.charAt(i));
return octal;
}
function Hexadecimal(decimal) {
let hex = "";
while (decimal > 0) {
let remainder = decimal % 16;
if (remainder >= 0 && remainder <= 9)
hex = remainder.toString() + hex;
else
hex = String.fromCharCode(65 + remainder % 10) + hex;
decimal = Math.floor(decimal / 16);
}
return hex;
}
function HTML(decimal) {
let html = decimal.toString();
html = "&#"+ html + ";";
return html;
}
function ASCIIlookuptable(ch) {
let decimal = ch.charCodeAt(0);
console.log("Octal value: " + Octal(decimal));
console.log("Decimal value: " + decimal);
console.log("Hexadecimal value: " + Hexadecimal(decimal));
console.log("HTML value: " + HTML(decimal));
}
// Drive code function
let ch = "@";
ASCIIlookuptable(ch);
Output
Octal value: 100 Decimal value: 64 Hexadecimal value: 40 HTML value: @
Time Complexity: O(log8(Decimal)), as we are using a loop and in each traversal we are decrementing N by floor division of 8.
Auxiliary Space: O(log8(Decimal)), as we are using extra space for the answer.
