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Im trying to define the variable in C programming.
Does anyone how to do it and the difference of data type while defining it?

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int - number values only, no letters int a = 5;
char - letters or numbers, but only 1 at a time char a = 'b';
int array - number values only, no letters int a[5] = {1,2,3,4,5};
char array - aka string, letters or numbers, one per array slot char a[5] = {'a','b','c','d','e'};
(there are other ways of defining arrays but these should do for now)

how about your OWN type?

typedef struct hotelroom { int room; char roomname[10]; int dailycharge; int floor; } hotelroom;

Now we have a hotel room type made up of char arrays and ints

hotelroom room1; strcpy(room1.roomname, "3B"); room1.dailycharge = 20; room1.floor = 3;

Now we have set the data values of our special type variable

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Defining a variable in C is quite straightforward, all you need to do is follow these steps:

  • Decide what you're going to put in the variable, and choose the appropriate datatype.
  • Decide a name for your variable.
  • Assign a value to the variable.

For example, to store your age, you would approach defining your variable like so:

  • We know the age is going to be an integer, which means it is a whole number having no decimal value. In C, the datatype for storing integers is called int, so that's our data type.

  • Our variable stores an age, so we might as well call it age.

  • We can now store any number we want in our age variable (shh, C won't know).

Once you've done those 3 things, you can write out your declaration like so

int age = 42;

(Notice that ; in the end, that's something you can't forget)

And there you have it, You've just declared your variable!

Here are some other data types you can use:

float pi = 3.14; char grade = 'A';

If you wanted to store a string, or a sequence of characters, you would use a 'character array' (you don't have to worry about what this means, you'll learn what arrays are later)

char[] username = "zeno99";

You can find dozens of great C tutorials that will make learning it easier, here are a couple ones I found

Hope this helped!

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@JustARatherRidi Love this answer! Wish I could up vote it twice! Very well put together and a lot of explanation.

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@EchoCoding Thank you! That means a lot :)

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Almost just like any other programming language.
For example.
int foo = 22;
string Da = "Hello World!";
Remember google is a good resource for this as well!

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@ryanhallihan I've got news for you buddy, there is no 'string' datatype in C, what you should do is use a character array, like so

char[] name = "ryan";
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@JustARatherRidi Oops! Sorry!

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@ryanhallihan No problem, but try and be a bit more careful when you're posting an answer to someone relatively newer than you are. They might think they're doing something wrong, which might confuse them further.