using System;
namespace mc
{
public class Program
{
public static void Main(string[] args)
{
Console.WriteLine("> ");
var line = Console.ReadLine();
if (string.IsNullOrWhiteSpace(line))
return;
var lexer = new Lexer(line);
while(true) {
var token = lexer.NextToken();
if(token.Kind == SyntaxKind.EndOfFileToken)
break;
Console.Write($"{token.Kind}: '{token.Text} '");
if(token.Value != null) {
Console.Write($"{token.Value}");
}
Console.WriteLine();
}
}
}
enum SyntaxKind {
NumberToken,
WhiteSpaceToken,
PlusToken,
MinusToken,
StarToken,
ForwordSlashToken,
OpenParenthesisToken,
CloseParenthesisToken,
BadToken,
EndOfFileToken,
}
class SyntaxToken {
public SyntaxToken(SyntaxKind kind, int position, string text, Object value ){
Kind = kind;
Position = position;
Text = text;
Value = value;
}
public SyntaxKind Kind {get;}
public int Position {get;}
public string Text {get;}
public Object Value {get;}
}
class Lexer
{
private readonly string _text;
private int _position;
public Lexer(string text) {
_text = text;
}
private void Next () {
_position ++ ;
}
private char Current {
get {
if(_position > _text.Length){
return '\0';
}
return __text[_position];
}
}
public SyntaxToken NextToken() {
// +, - , *, %
// <number> <whiteSpace>
if(Current == '\0'){
return new SyntaxToken(SyntaxKind.EndOfFileToken, _position++,'\0', null);
}
if(char.IsDigit(Current)){
var start = _position;
while(char.IsDigit(Current)) {
Next();
}
var lenght = _position - start;
var token = _text.Substring(start, lenght);
int.TryParse(token, out var value);
return new SyntaxToken(SyntaxKind.NumberToken, start , token, value);
}
else if(char.IsWhiteSpace(Current)){
var start = _position;
while(char.IsWhiteSpace(Current)) {
Next();
}
var lenght = _position - start;
var token = _text.Substring(start, lenght);
int.TryParse(token, out var value);
return new SyntaxToken(SyntaxKind.WhiteSpaceToken, start , token, null);
}
else if(Current == '+')
{
return new SyntaxToken(SyntaxKind.PlusToken,_position++,'+',null);
}
else if(Current == '-')
{
return new SyntaxToken(SyntaxKind.MinusToken,_position++,'-',null);
}
else if(Current == '*')
{
return new SyntaxToken(SyntaxKind.StarToken,_position++,'*',null);
}
else if(Current == '/')
{
return new SyntaxToken(SyntaxKind.ForwordSlashToken,_position++,'/',null);
}
else if(Current == '(')
{
return new SyntaxToken(SyntaxKind.OpenParenthesisToken,_position++,')',null);
}
else if(Current == ')')
{
return new SyntaxToken(SyntaxKind.CloseParenthesisToken,_position++,'(',null);
}
return new SyntaxToken(SyntaxKind.BadToken, _position++,_text.Substring(_position -1, 1),null);
}
}
} Write, Run & Share C# code online using OneCompiler's C# online compiler for free. It's one of the robust, feature-rich online compilers for C# language, running on the latest version 8.0. Getting started with the OneCompiler's C# compiler is simple and pretty fast. The editor shows sample boilerplate code when you choose language as C# and start coding.
OneCompiler's C# online compiler supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample program which takes name as input and print your name with hello.
using System;
namespace Sample
{
class Test
{
public static void Main(string[] args)
{
string name;
name = Console.ReadLine();
Console.WriteLine("Hello {0} ", name);
}
}
}
C# is a general purpose object-oriented programming language by Microsoft. Though initially it was developed as part of .net but later it was approved by ECMA and ISO standards.
You can use C# to create variety of applications, like web, windows, mobile, console applications and much more using Visual studio.
| Data Type | Description | Range | size |
|---|---|---|---|
| int | To store integers | -2,147,483,648 to 2,147,483,647 | 4 bytes |
| double | to store large floating point numbers with decimals | can store 15 decimal digits | 8 bytes |
| float | to store floating point numbers with decimals | can store upto 7 decimal digits | 4 bytes |
| char | to store single characters | - | 2 bytes |
| string | to stores text | - | 2 bytes per character |
| bool | to stores either true or false | - | 1 bit |
datatype variable-name = value;
When ever you want to perform a set of operations based on a condition or set of few conditions IF-ELSE is used.
if(conditional-expression) {
// code
}
else {
// code
}
You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.
Switch is an alternative to If-Else-If ladder.
switch(conditional-expression) {
case value1:
// code
break; // optional
case value2:
// code
break; // optional
...
default:
// code to be executed when all the above cases are not matched;
}
For loop is used to iterate a set of statements based on a condition.
for(Initialization; Condition; Increment/decrement) {
// code
}
While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.
while(condition) {
// code
}
Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.
do {
// code
} while (condition);
Array is a collection of similar data which is stored in continuous memory addresses. Array values can be fetched using index. Index starts from 0 to size-1.
data-type[] array-name;
Method is a set of statements which gets executed only when they are called. Call the method name in the main function to execute the method.
static void method-name()
{
// code to be executed
}