Preface

Just re-stating that I’m going to compare what I learn about C# with JavaScript.

Today, we’ll be going over these statements:

• Decision Statements
  1. if
  2. else if
  3. else
  4. switch
• Loops (or as they call it, repetition)
  1. for
  2. foreach
  3. while
  4. do

The if Statement

C#

string response = "Yes";
if (response == "Yes")
{
    // statements that will execute if the value of the response variable is
    // yes, will be placed here.
}

JavaScript

let response = "Yes";
if (response === "Yes") {
    // statements that will execute if the value of the response variable is
    // yes, will be placed here.
}

Just a JavaScript refresher:

• === checks if the two statements are the same value and type.
• == checks only if the two statements are the same value.
• = is an assignment operator, like let i = 5;

=== does not exist in C#. Otherwise, the syntax for if statements are very similar:

if () {}

if else Statements

C#

string response;
if (response == "connection_failed")
{
    // Block of code executes if the value of the response variable is "connection_failed".
}
else
{
    // Block of code executes if the value of the response variable is not "connection_failed".
}

JavaScript

let response;
if (response === "connection_failed") {
    // Block of code executes if the value of the response variable is "connection_failed".
}
else {
    // Block of code executes if the value of the response variable is not "connection_failed".
}

Once again, almost identical (besides the string response declaration and lack of === in C#)

else if Statements

C#

string response;
if (response == "connection_failed")
{
    // Block of code executes if the value of the response variable is "connection_failed".
}
else if (response == "connection_error")
{
    // Block of code executes if the value of the response variable is "connection_error".
}
else
{
    // Block of code executes if the value of the response variable is neither above responses.
}

JavaScript

let response;
if (response === "connection_failed") {
    // Block of code executes if the value of the response variable is "connection_failed".
}
else if (response === "connection_error") {
    // Block of code executes if the value of the response variable is "connection_error".
}
else {
    // Block of code executes if the value of the response variable is neither above responses.
}

Once again, almost identical! Not too bad.

The switch Statement

C#

string response;
switch (response)
{
   case "connection_success":
      // Block of code executes if the value of response is "connection_success".
      break;
   case "connection_failed":
   case "connection_error":
      // Block of code executes if the value of response is "connection_failed"
      // or "connection_error;
      break;
   default:
      // Block executes if none of the above conditions are met.
      break;
}

JavaScript

let response;
switch (response) {
   case "connection_success":
      // Block of code executes if the value of response is "connection_success".
      break;
   case "connection_failed":
   case "connection_error":
      // Block of code executes if the value of response is "connection_failed"
      // or "connection_error;
      break;
   default:
      // Block executes if none of the above conditions are met.
      break;
}

Wow, they’re the same! Wonderful!

The Loops (for Loop)

C#

// Basic Format
for ([initializers]; [condition]; [iterator])
{
   // code to repeat goes here
}

//for Loop
for (int i = 0 ; i < 10; i++)
{
    // Code to execute.
}

JavaScript

// Basic Format
for ([initializers]; [condition]; [iterator]) {
   // code to repeat goes here
}

//for Loop
for (let i = 0 ; i < 10; i++) {
    // Code to execute.
}

That’s nice, they’re the same again. Of course, you must remember that in C# you have to declare the type of the variable (in this case, int)

foreach Loops

Introducing Arrays in C#!

C#

string[] names = new string[10];

// Process each name in the array.
foreach (string name in names)
{
    Console.WriteLine($"{name}");
}

string[] names = new string[10]; is how you make arrays in C#.

• string[] means the new array holds strings
• names is giving the array the name of names
• new string[10] is declaring the new array with a length of 10.

JavaScript

let names = [];

// Process each name in the array.
names.forEach(function(name) {
    console.log(name);
});

Ok, now there are some big differences:

• In JavaScript, there is no need to declare the length of the array when initializing it.

• The foreach methods themselves are also different in both languages:

  • JavaScript uses the general format arrayName.forEach(function(item){});
  • C# uses foreach (type item in arrayName){}

C#’s foreach formatting is similar to if(){}, while JavaScript requires that you use function() to define what code executes forEach item in the array.

The while Loop

C#

string response = PromptUser();
while (response != "Quit")
{
    // Process the data.
    response = PromptUser();
}

JavaScript

let response = prompt();
while (response !== "Quit") {
    // Process the data.
    response = prompt();
}

Back to similar territory. Note that the JavaScript uses !== while C# has no such operator.

The do Loop

C#

do
{
    // Process the data.
    response = PromptUser();
} while (response != "Quit");

JavaScript

do {
    // Process the data.
    response = prompt();
} 
while (response !== "Quit");

They’re similar! Both languages use the do...while loop to make sure the code in the do portion is executed at least once.

My thoughts

There are a lot of similarities in syntax between C# and JavaScript, at least for if statements and loops. So far, most of the differences are just due to how values are typed.

Next time, we’ll get into using methods and exceptions.