Xamarin: Branching and Looping

Branching and Looping

Eng Teong Cheah

Microsoft MVP Windows Development

Branching and Looping

C# branching and looping depends upon Boolean algebra. Before we understand looping, we need to understand Boolean algebra. Boolean means true or false. A condition can either be true or false.

Bool result = 1<2;

Console.WriteLine(result);

Here we can see 1 is less than 2 which is definitely true so result will be

assigned a value as true.

Jumping from one code block to other:

Jumping from one code block to another is done by goto statement. We can label a code block and jump to that code block by using that label.

start:

bool result = 1< 2;

Console.WriteLine(result);

goto start;

Console.ReadKey();

Here code will never reach last statement as it will jump again and again to

start label.

Branching

Branching

Branching can be done using if else construct or ternary operator or Switch statement.- If else construct is used when we have more than one condition’s.- Ternary operator is used when we have single condition evaluating to true or false.- Switch case is use when evaluation to multiple condition is done.

Using if else to calculate input is even or odd.

int result;

Console.WriteLine("Enter input variable");

result = Convert.ToInt32(Console.ReadLine())% 2;

if (result ==0) //condition

{

//if result is even

Console.WriteLine("input is even");

}

else

{

//if result isodd

Console.WriteLine("input is odd");

}

Console.ReadKey();

Using ternary operator? to calculate input is even or odd:General Syntax is: (condition) ? trueresult : falseresult

int result;

Console.WriteLine("Enter input variable");

result = Convert.ToInt32(Console.ReadLine());

string output =result == 0 ? "even" : "odd";

Console.WriteLine("input is {0}",output);

Console.ReadKey();

Using switch operator to calculate input is even or odd:

int result;

Console.WriteLine("Enter input variable");

result = Convert.ToInt32(Console.ReadLine());

switch(result % 2) //condition

{

case 0:

Console.WriteLine("input is even");

break;

case 1:

Console.WriteLine("input is odd");

break;

default:

break;

}

Console.ReadKey();

Break statement is compulsory in C# switch statement.

Looping in C#

Looping in C#

Looping can be done in C# in 4 ways. Four ways are as follows:- do while loop

- while loop

- for loop

- foreach loop

do while loop

do while loops are used when first value can be printed without any operation on it.For example: When we need to output a statement balance after getting money from ATM.

// printing 1 to 10 using do while loop

int i=1;

do

{

Console.WriteLine(i++);

}

while (i <=10);

while loop

while loop is used when a loop continues to work till a condition evaluated to true.For example: Working with Reader object from database.

// printing 1 to 10 using while loop

int j = 1;

while (j <= 10)

{

Console.WriteLine(j++);

}

for loop

for loop can be used when we know no of iteration needs to be done.

// printing 1 to 10 using for loop

for (int k = 1; k <= 10; k++)

{

Console.WriteLine(k);

}

Console.ReadKey();

foreach loop

foreach loop in C# is used to loop through a collection.

//program to print 1 to 10 using foreach loop

int[] arr = new int[] { 1, 2, 3,4, 5, 6, 7, 8, 9, 10 };

foreach (int item in arr)

{

Console.WriteLine(item);

}

Console.ReadKey();

Demo

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Reference