Basic Things

Structure

Before going into C# programming, we should look at the minimum structure C# programm.

using System;
namespace Program {
    class Program {
        static void Main (string[] args) {
            Console.WriteLine("Hello World!");
            Console.ReadLine();
        }
    }
}

When this code is compiled and executed, it will display Hello World"!.

note

• C# is case sensitive !
• All the statement/declaration must end with a semicolon (;).
• The program execution starts at the Main method.

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Input and Outputs

The command to input is Console.WriteLine();.

However, the command to output or display is Console.ReadLine();.

Arithmetic Operator

Arithmetic operator are simple mathematic operation. The following table shows all the arithmetic operator -

Operator	Description	Example
+	Adds two operand	A + B = 30
-	Substract second operand from the list	A - B = 10
*	Mutiples both operands	A * B = 200
/	Divides numerator by de-numerator	B/A = 2
%	Modulus Operator and remainder of after an integer division	B/A=2
++	Increment oprator increases integer value by one	A ++= 11
--	Decrement operator decreases integer value by one	A --= 9

Relational Operators

Relational operator are operator that defines a replation between two entities.

Operator	Description	Example
==	Checks if the values of two operands are equal or not, if yes then condition becomes true.	(A == B) is not true
!=	Checks if the values of two operands are equal or not, if values are not equal then condition becomes true.	(A!=B) is true.
>	Checks if the value of left operand is greater than the value of right operand, if yes then condition becomes true.	(A>B) is not true
<	Checks if the value of left operand is less than the value of right operand, if yes then condition becomes true.	(A < B) is true.
>=	Checks if the value of left operand is greater than or equal to the value of right operand, if yes then condition becomes true.	(A >= B) is not true.
<=	Checks if the value of left operand is less than or equal to the value of right operand, if yes then condition becomes true.	(A <= B) is true.

Logical Operator

Logical operator are operator that connect two or more expression.

Operator	Description	Example
&&	Called Logical AND operator. If both the operands are non zero then condition becomes true.	(A && B) is false.
!	Called Logical NOT Operator. Use to reverses the logical state of its operand. If a condition is true then Logical NOT operator will make false.	!(A && B) is true.

Assign Operator

The assignment Operator is the operator used to assign a new value to a variable.

Operator	Description	Example
=	Simple assignment operator, assigns value from right side operands to left side operand	X = A
+=	Add AND assignment operator, it adds right operand to the left operand and assign the result to left operand	X += A is the same as X = A + X
-=	Substract AND assignment operator, it subtracts right operand from the left operand and assign the result to the left operand	X -= A
*=	Multiply AND assignment operator, It multiplies right operand with the left operand and assign the result to left operand	C *= A
/=	Divide AND assignment operator, It divides left operand with the right operand and assign the result to left operand	C /= A
%=	Modulus AND assignment operator, It takes modulus using two operands and assign the result to left operand	C %= A

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Concatenation

Concatenation is the process of appending one string to the end of another string. You concatenate strings by using the + operator.

using System;

namespace Program {

    class Program {
    
        static void Main(string[] args) {
            Console.WriteLine("Hello World!" + "Welcome to...");
            Console.ReadLine();
        }
    }
}

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Key Words

• Relational Operator

• Logical Operator

• Operand - is a value

• Assign

• Variable - is a "storage" that contains the information

• Datatype - allocates a specific memory

• Concatenation

• Expression - is a mathematical logic that return a value. For example, A + B = X

• Decision

• Statements

• Algorihm - is a set of instruction

• Maths Function -

  • Ceiling

  • Floor

  • Math.Abs, etc..

• Control Structure - is used to specify the flow of the program: iteraion, sequence and

• Iteration - are loops: while loop, do while loop, for loop and for each loop. It needs to have a control variable.

• Control Variable -

• Block Statements - is a where instruction are inside the statements, usually condition

• Branch Statements

• Sequence

• Syntax - is the language rule

• Concatenation

• Function - is a block of code that performs a specific task

  it will return a value

• Procedure - is a block of code that performs a specific task that does not return a value.

• Method - combines fuction and procedure together

• Library - is a collection of prewritten code that performs specific

• Access Specifier

• Arguments

• Parameters

• Subroutine

• Arrays:

  • FindAll
  • Findwith
  • ArrayLenght

• Static