SLR1 Useful Code to learn

Question 1

What code counts the elements in an array?

Answer 1

[int] numberArray.Count()
[string] stringArray.Count()

Question 2

What should the statement switch be used for?

Answer 2

Use the switch statement to select one of many code blocks to be executed.

Question 3

Code for a switch:

Answer 3

switch(expression)
{
case x:
// code block
break;
case y:
// code block
break;
default:
// code block
break;
}

Question 4

How does the switch statement work?

Answer 4

This is how it works:

• The switch expression is evaluated once
• The value of the expression is compared with the values of each case
• If there is a match, the associated block of code is executed

Question 5

Why is the break needed in a switch statement?

Answer 5

When C# reaches a break keyword, it breaks out of the switch block.

This will stop the execution of more code and case testing inside the block.

Question 6

default code in switch code and why its needed:

Answer 6

default:
Console.WriteLine(“Looking forward to the Weekend.”);
break;

default keyword is optional and specifies some code to run if there is no case match

Question 7

shorthand for if else statements:

Answer 7

variable = (condition) ? expressionTrue : expressionFalse;

Question 8

continue statement

Answer 8

The continue statement breaks one iteration (in the loop), if a specified condition occurs, and continues with the next iteration in the loop

if (i == 4)
{
continue;
}

Question 9

creating an array

Answer 9

string[] cars;

Question 10

how to output the first elements of an array:

string[] cars = {“Volvo”, “BMW”, “Ford”, “Mazda”};

Answer 10

Console.WriteLine(cars[0]);
// Outputs Volvo

Question 11

Changing the first element in an array to Opel

string[] cars = {“Volvo”, “BMW”, “Ford”, “Mazda”};

Answer 11

cars[0] = “Opel”;
Console.WriteLine(cars[0]);

Question 12

Printing the length of the array

string[] cars = {“Volvo”, “BMW”, “Ford”, “Mazda”};

Answer 12

Console.WriteLine(cars.Length);

Question 13

Declaring an array and adding new values to it (cars again)

Answer 13

// Declare an array
string[] cars;

// Add values, using new
cars = new string[] {“Volvo”, “BMW”, “Ford”};

Question 14

Print all the elements in the array:

string[] cars = {“Volvo”, “BMW”, “Ford”, “Mazda”};

Answer 14

for (int i = 0; i < cars.Length; i++)
{
Console.WriteLine(cars[i]);
}

Question 15

What type of loop is used exclusively to loop through an array?

string[] cars = {“Volvo”, “BMW”, “Ford”, “Mazda”};

Answer 15

a foreach loop

foreach (string i in cars)
{
Console.WriteLine(i);
}