6. Scientific calculator supporting addition, subtraction, multiplication, division, square-root, square, cube, sin, cos, tan, Factorial, inverse, modulus

This is a fairly simple implementation of a console calculator. It only takes 2 number expressions ( ex: 1 + 1 ) as well as / commands for most other functions, except factorial ( n! ). Very little error checking is being done. All sorts of invalid inputs will cause this to throw exceptions.

using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace lrn2csharp6_console { class Program { private static String Version = "0.0"; static void Main( string[ ] args ) { Console.WriteLine( "neSP: Calc v" + Version ); Console.WriteLine( "---------------------------------" ); Console.WriteLine( "Enter Command. ( example: /help )" ); int end = 0; while ( end == 0 ) { String exp = ""; Console.Write( ":" ); try { exp = Console.ReadLine( ); } catch ( InvalidOperationException ) { Console.WriteLine( "Not a valid command." ); exp = ""; } if ( exp.Length == 0 ) { // empty command } else if ( exp.ToCharArray( ).First( ) == '/' ) { if ( exp.Split( ' ' ).ToString( )[ 0 ].Equals( "/help" ) ) { Console.WriteLine( "You are being helped:" ); Console.WriteLine( "/help - bring up this help system." ); Console.WriteLine( "/quit or /q - quit program." ); Console.WriteLine( "/prime n - generate prime numbers from 2 to n." ); Console.WriteLine( "/factor numerator/denominator - factors fraction." ); Console.WriteLine( "/sqrt n - finds the square root of n." ); Console.WriteLine( "/cbrt n - finds the cube root of n." ); Console.WriteLine( "/sin n - finds sine of n." ); Console.WriteLine( "/cos n - finds cosine of n." ); Console.WriteLine( "/tan n - finds tangent of n." ); Console.WriteLine( "/inv numerator/denominator - finds inverse of fraction." ); Console.WriteLine( "n! - finds factorial of n." ); } else if ( exp.Split( ' ' )[ 0 ].Equals( "/quit" ) || exp.Split( ' ' )[ 0 ].Equals( "/q" ) ) { end = 1; } else if ( exp.Split( ' ' )[ 0 ].Equals( "/primes" ) ) { Console.Write( "primes:" ); prime( Convert.ToInt32( exp.Split( ' ' )[ 1 ] ) ); Console.WriteLine( ); } else if ( exp.Split( ' ' )[ 0 ].Equals( "/factor" ) ) { } else if ( exp.Split( ' ' )[ 0 ].Equals( "/sqrt" ) ) { Console.WriteLine( Math.Sqrt( Convert.ToDouble( exp.Split( ' ' )[ 1 ] ) ) ); } else if ( exp.Split( ' ' )[ 0 ].Equals( "/cbrt" ) ) { double power = 1.0 / 3.0; Console.WriteLine( Math.Pow( Convert.ToDouble( exp.Split( ' ' )[ 1 ] ), power ) ); } else if ( exp.Split( ' ' )[ 0 ].Equals( "/sin" ) ) { Console.WriteLine( Math.Sin( Convert.ToDouble( exp.Split( ' ' )[ 1 ] ) ) ); } else if ( exp.Split( ' ' )[ 0 ].Equals( "/cos" ) ) { Console.WriteLine( Math.Cos( Convert.ToDouble( exp.Split( ' ' )[ 1 ] ) ) ); } else if ( exp.Split( ' ' )[ 0 ].Equals( "/tan" ) ) { Console.WriteLine( Math.Tan( Convert.ToDouble( exp.Split( ' ' )[ 1 ] ) ) ); } else if ( exp.Split( ' ' )[ 0 ].Equals( "/inv" ) ) { String fraction = exp.Replace( "/inv ", "" ); double numer = Convert.ToDouble( fraction.Split( '/' )[ 0 ] ); double denom = Convert.ToDouble( fraction.Split( '/' )[ 1 ] ); Console.WriteLine( denom / numer ); } else { Console.WriteLine( "Invalid command ( " + exp + " ) supplied." ); } } else if ( exp.Contains( '!' ) ) { int f = Convert.ToInt32( exp.Split( '!' )[ 0 ] ); Console.WriteLine( f ); int total = 1; for ( int i = 0; i < f; i++ ) { total = total * ( i + 1 ); } Console.WriteLine( total ); } else { calc( exp ); } } } static void calc( String expression ) { String[ ] stack = expression.Split( ' ' ); Console.WriteLine( doCalc( Convert.ToDouble( stack[ 0 ] ), Convert.ToChar( stack[ 1 ] ), Convert.ToDouble( stack[ 2 ] ) ) ); } static double doCalc( double left, char theOperator, double right ) { double total = 0.0; if ( theOperator == '+' ) { total = add( left, right ); } else if ( theOperator == '-' ) { total = subtract( left, right ); } else if ( theOperator == '*' ) { total = multiply( left, right ); } else if ( theOperator == '/' ) { total = divide( left, right ); } else if ( theOperator == '^' ) { total = Math.Pow( left, right ); } else if ( theOperator == '%' ) { total = mod( Convert.ToInt32( left ), Convert.ToInt32( right ) ); } return total; } static double add( double num, double num2 ) { return ( num + num2 ); } static double subtract( double num, double num2 ) { return ( num - num2 ); } static double multiply( double num, double num2 ) { return ( num * num2 ); } static double divide( double num, double num2 ) { if ( num2 == 0 ) { Console.WriteLine( "ERROR: Division by zero." ); return num; } else { return ( num / num2 ); } } static int mod( int num, int num2 ) { return ( num % num2 ); } static void prime( int num ) { int count = 0; for ( int _i = 2; _i < num; _i++ ) { if ( !isPrime( _i ) ) { if ( ( count % 10 ) == 0 ) Console.WriteLine( ); Console.Write( " {0,6}", _i ); count++; } } } static bool isPrime( int num ) { bool notPrime = false; for ( int k = num - 1; k > 1 && !notPrime; k-- ) { if ( num % k == 0 ) notPrime = true; } return notPrime; } } }

4. Reynolds number is calculated using formula (D*v*rho)/mu Where D = Diameter, V= velocity, rho = density mu = viscosity Write a program that will accept all values in appropriate units (Don't worry about unit conversion) If number is < 2100, display Laminar flow, If it's between 2100 and 4000 display 'Transient flow' and if more than '4000', display 'Turbulent Flow' (If, else, then...)

5. Modify the above program such that it will ask for 'Do you want to calculate again (y/n), if you say 'y', it'll again ask the parameters. If 'n', it'll exit. (Do while loop)

While running the program give value mu = 0. See what happens. Does it give 'DIVIDE BY ZERO' error? Does it give 'Segmentation fault..core dump?'. How to handle this situation. Is there something built in the language itself? (Exception Handling)

using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace lrn2csharp4_5 { class Program { static void Main( string[ ] args ) { char answer = 'y'; Console.WriteLine( "Today we are going to calculate Reynolds Number (D*v*rho)/mu" ); while ( answer.Equals( 'y' ) ) { try { calcReynolds( ); } catch ( System.DivideByZeroException dbze ) { Console.WriteLine( dbze.Message ); } Console.Write( "Do you want to calculate again (y/n): " ); try { answer = Convert.ToChar( Console.ReadLine( ) ); } catch ( System.FormatException ) { answer = 'n'; } } } static void calcReynolds( ) { Console.Write( "Enter Diameter: " ); double d = Convert.ToDouble( Console.ReadLine( ) ); Console.Write( "Enter Velocity: " ); double v = Convert.ToDouble( Console.ReadLine( ) ); Console.Write( "Enter Density: " ); double rho = Convert.ToDouble( Console.ReadLine( ) ); Console.Write( "Enter Viscosity: " ); double mu = Convert.ToDouble( Console.ReadLine( ) ); // C# actually handles divide by zero well and wont throw an exception automatically, so do it manually if ( mu.Equals( 0 ) ) throw new System.DivideByZeroException( "Cannot divide by zero. Viscosity was zero. You erred." ); double reynolds = ( d * v * rho ) / mu; if ( reynolds < 2100 ) Console.WriteLine( "Laminar flow (" + reynolds + ")" ); else if ( reynolds >= 2100 && reynolds <= 4000 ) Console.WriteLine( "Transient flow (" + reynolds + ")" ); else Console.WriteLine( "Turbulent flow (" + reynolds + ")" ); } } }

3. Accepting series of numbers, strings from keyboard and sorting them ascending, descending order. using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading; namespace lrn2CSharp3 { class Program { static void Main( string[ ] args ) { Console.Write( "Please enter the number of items you wish to enter: " ); int num_item = Convert.ToInt32( Console.ReadLine( ) ); int[ ] nums = new int[ num_item ]; for ( int i = 0; i < num_item; i++ ) { Console.Write( "Item " + i + ": " ); nums[ i ] = Convert.ToInt32( Console.ReadLine( ) ); } qsort( nums ); foreach ( int num in nums ) Console.Write( num.ToString( ) + " " ); Console.WriteLine( "" ); nums = reverse( nums ); foreach ( int num in nums ) Console.Write( num.ToString( ) + " " ); Console.WriteLine( "" ); Console.WriteLine( "Press esc to exit." ); while ( !keyPressHandler( Console.ReadKey( true ) ) ) { Thread.Sleep( 250 ); /* no op */ } } static void swap<T>( ref T lhs, ref T rhs ) { T temp; temp = lhs; lhs = rhs; rhs = temp; } static void qsort( int[ ] nums ) { qs( nums, 0, nums.Length - 1 ); } static void qs( int[ ] items, int left, int right ) { int i, j; int x; i = left; j = right; x = items[ ( left + right ) / 2 ]; do { while ( ( items[ i ] < x ) && ( i < right ) ) i++; while ( ( x < items[ j ] ) && ( j > left ) ) j--; if ( i <= j ) { swap<int>( ref items[ i ], ref items[ j ] ); i++; j--; } } while ( i <= j ); if ( left < j ) qs( items, left, j ); if ( i < right ) qs( items, i, right ); } static int[ ] reverse( int[ ] items ) { int[ ] reversed = new int[ items.Length ]; int j = 0; for ( int i = items.Length - 1; i >= 0; i-- ) { reversed[ j ] = items[ i ]; j++; } return reversed; } protected static Boolean keyPressHandler( ConsoleKeyInfo input ) { if ( input.Key == ConsoleKey.Escape ) return true; return false; } } }

2. Fibonacci series, swapping two variables, finding maximum/minimum among a list of numbers. using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading; namespace lrn2Csharp2 { class Program { static void Main( string[ ] args ) { int fibs = 21; int[ ] fib_series = new int[ fibs ]; Console.WriteLine( "Outputing Fib 0 through " + fibs ); for ( int i = 0; i < fib_series.Length; i++ ) { fib_series[ i ] = fibonacci( i ); } printArray( fib_series ); Console.WriteLine( "" ); Console.WriteLine( "Max in Fib Series: " + max( fib_series ) ); Console.WriteLine( "Min in Fib Series: " + min( fib_series ) ); Console.WriteLine( "Swapping front with end: " ); swap<int>( ref fib_series[ 0 ], ref fib_series[ fib_series.Length - 1 ] ); printArray( fib_series ); Console.WriteLine( "" ); Console.WriteLine( "Press esc to exit." ); while ( !keyPressHandler( Console.ReadKey( true ) ) ) { Thread.Sleep( 250 ); /* no op */ } } static void swap<T>( ref T lhs, ref T rhs ) { T temp; temp = lhs; lhs = rhs; rhs = temp; } public static int fibonacci( int n ) { if ( n <= 1 ) { return n; } else { return fibonacci( n - 1 ) + fibonacci( n - 2 ); } } public static int max( int[ ] n ) { int max = n[ 0 ]; for ( int _i = 0; _i < n.Length; _i++ ) { if ( n[ _i ] > max ) max = n[ _i ]; } return max; } public static int min( int[ ] n ) { int min = n[ 0 ]; for ( int _i = 0; _i < n.Length; _i++ ) { if ( n[ _i ] < min ) min = n[ _i ]; } return min; } public static void printArray( int[ ] n ) { for ( int _i = 0; _i < n.Length; _i++ ) { Console.Write( n[ _i ] + " " ); } } protected static Boolean keyPressHandler( ConsoleKeyInfo input ) { if ( input.Key == ConsoleKey.Escape ) return true; return false; } } }

It's been a while since I've made an actual post, but I felt the urge. I do alot of programming (many different languages), so after I read this interview I thought i'd share it.

Looks like the twitter integration has worked pretty well.

Yes I'm still around. I got lazy and busy at the same time, so no updates since the last one till now. I was bored and have nothing to do till christmas stuff starts tomorrow so I started messing around on the web. Read an article "Twitter, Flickr, Facebook Make Blogs Look So 2004" aka "The Blog is Dead". And so it is! Though not for the reasons the article explains, mine is dead right now... well... I already mentioned that. Anyway, I made a twitter account and hopefully January I will force myself to add my twitter feed to my feed eater here at IDT.

Don't hold your breath though. I wouldn't want any blood on my hands.