Jun 25, 2003  You will have to declare variables to input the data. Luckily, declaring variables in C is very easy. This simple program gets the user's age as input and displays it back to the screen. Here is the source code: #include using namespace std; int main int age; cout C Program'. Apr 11, 2020  Converting a String to a Number; Declare and initialize a String. A string is a simple array with char as a data type. 'C' language does not directly support string as a data type. Hence, to display a string in 'C', you need to make use of a character array. The general syntax for declaring a variable as a string is as follows. String variables are declared by using the string type, however as strings aren't actually 'primitive' types in C (and are instead defined by the standard library of stuff that comes bundled with C), you are required to #include string to use this data-type. An example of string declaration and initialization to a string constant is as follows. THE WORLD'S LARGEST WEB DEVELOPER SITE. Declare Variables Declare Multiple Variables Identifiers Constants. C User Input C Data Types. Strings are used for storing text. A string variable contains a collection of characters surrounded by double quotes: Example. A char variable in C is designed to hold an ASCII character, an int an integer number, and a double a floating-point number. Similarly, a pointer variable is designed to hold a memory address. You declare a pointer variable by adding an asterisk (.) to the end of the type of the object that the.

Re “How can I declare array of strings C?”, why would you want to do that??? That would be an exceedingly bizarre thing to do in C! But if you insist, you would do that the same in C as you would in C: code// Make a dangerous array of 20 s.

Arrays, in C++, are simply arrangements of 'objects' -- in the basic usage we'll be using in this tutorial, we will be using arrays to simply store lists of data (of a certain because each piece of data stored (whether it be an integer, string, or something entirely different) has a number assigned to it that it can be referenced by. Cla guitar vst free download. This is called the index, and the index number simply counts up from 0 as the array gets bigger - so the first element in the array would have the index of 0, the second the index of 1, etc.

Obviously storing data in this tabular-like manor is very useful in real world applications - a classic example that is usually given is pupils' scores in a test. Perhaps each student got a score out of 100 for their test - this data would be best stored in an integer array. In the real world the scores would probably be recorded in a text file or something similar, but we could always build in functionality to read this file and then store that data in an array inside our application.

Arrays can be created in C++ very much like 'normal variables' (with a) , followed by the index number of the element we wish to target in square brackets, followed by an equals sign and then the value we wish to set it to (and then obviously a semi-colon to end the line). So if we wanted to initialize the first element (of index 0) in our array to the value '15', we could write the following:

The same could also be done for the scores of the other members of the class (elements of the array from index 0 to index 29). If we then wanted to use these values later (for example if we wanted to cout one or all of the elements), we can access a certain element of the array just as we did when we were assigning values to each element - by writing the array name and then the index number in square brackets. So we could output the first element in the array (remember, this is the one with the index of 0!) by writing something like cout << ClassScores[0];.

You may have noticed when we learnt how to initialize the elements in arrays earlier, that the process was extremely long and drawn out (imagine having to initialize hundreds of array elements!) - luckily there is an easier way to initialize the elements in an array. Instead of individually setting each element to a certain value (which can be done at any point in the program, not just at element initialization) we can actually initialize the elements when we declare the array! This method of initialization is accomplished by simply shoving an equals sign after the declaration of the array and then specifying the different array elements, with commas separating them, in curly brackets. This method doesn't require any value in the square brackets either as the compiler can calculate how many elements we are initializing and set the array size to that! To show this method of initialization, let's just set some values for each score in the class at the array declaration - let's cut it down to 20 this time for the sake of simplicity:

Java Declare String Variable

With an array declared and initialized, we can do a whole bunch of stuff with it! A nice example might be outputting all of the students' scores - unfortunately, however, there's no really easy and clean way to do this without knowing about 'loops' or some other fancy things, so for now we'll have to just repeat a bunch of code. Generally speaking when you feel your repeating a lot of code when C++ programming, there is probably a better way to accomplish what you're trying to do, but for now just go with it. I've cut the array down to 5 elements this time, simply because I don't want to have to copy and paste a single line 20 times - you'll learn about a more elegant solution to our problem of outputting array elements in the next tutorial.

Another really cool thing that you could do with arrays is trying to 're-create' the 'string', character arrays like 'H', 'e', 'l', 'l', 'o' were used -- character arrays of this kind can, unlike most, actually be outputted just by couting their name because they're so much like strings. It's worth nothing that when creating character arrays like these, however, you should also add another character onto the array, which is a 'null character' which shows where the string ends - this is called the null termination of a string, and the null character is expressed via '0'.

'Real' strings can actually be treated just like character arrays in some circumstances too - using square brackets and an index number gets a certain character of the string (for example string_name[1] of 'Hello' would be 'e'). If you're feeling up to the challenge, try moving a string variable defined in code (of a fixed length) like string one = 'Hello';, to a 'char' array of the same length using the information above. It probably seems a bit pointless, I know, but it's good practice with using arrays. If you don't feel up to the challenge, the code for doing such a thing (which once again would be a bit cleaner with 'loops'), is as follows:

Variables are an extremely core concept to most object orientated programming languages. I like to visualize a variable much like a box. We can put things in the box, we can take things out of the box, and at any point we can see what is inside the box. Each box also has a name to which we can refer to it by, and in C++, each box can only hold a certain type of data.

When we create variables we call this the variable declaration, and then when we set them for the first time, we call this the initialization. To declare a variable in C++, we write the function. To declare a basic integer variable called 'age', we could write the following:

From this point we can then refer to the variable by its name, so in this case, we can just write 'age' whenever we want to refer to the variable. To initialise the variable we can write its name, followed by the equals sign, followed by the value we want to set the variable to (followed by a semicolon). The value we set it to can be a constant (a value that doesn't change), or another variable of the same type. An operator is a symbol which has a certain meaning in the programming language, in this case, the equals operator, represented by the = symbol, is an operator which sets whatever is on the left of the operator to whatever is on the right.

The constant value we set the variable to depends on the to 5 with something like the following:

We can actually combine the variable declaration and initialization into one more-compact line, like the following:

The 'age' variable now contains the number '5', and we can refer to this '5' by writing 'age' anywhere in our program. We can also change the value of the variable at any point by using the equals operator as we did for the first initialization:

Although this seems purely for convenience at the moment (as we could just write '5', '3', or '21' in place of 'age'), trust me when I say that these become extremely useful and powerful when you start dealing with dynamic logic and user input (the latter of which we'll be covering later in this tutorial).

Just to give an example of accessing the contents of variables by using their names, we could create a new variable called 'age_two' which is set to the value of 'age', and then we can also try outputting one or both of these variables:

To be clear, all this code should be going into the basic program structure which we learnt how to create in the last tutorial. So we want our 'iostream' include for cout, cin, and some other stuff, we want the std namespace, and we want the majority of our code to be going in our 'main' function. So our full code to demonstrate variables so far, which you can compile and run at any point to test the functionality, is as follows:

Some number variables can handle positive and negative numbers, whereas 'unsigned' number variables can only handle positive numbers, although because of this restriction, can hold larger numbers. You can write the signed or unsigned keywords before the and 'short' - numbers with a decimal place in. Floats are accurate to around 6 or 7 digits and are declared using the float type. Float constants can be defined by simply writing a number with a decimal point followed by the 'f' notation. An example of a simple float declaration and initialization to a float constant is as follows:

Care must be taken, however, with float (and other decimal) operations, as rounding and precision problems to do with how the numbers are stored can trip you up (we don't have infinite memory for recurring decimals like 1/3 for example) -- I recommend reading this article for more information on this if you're interested.

Doubles

The 'double' or 'e'. Character variables are declared by using the char type, and character constants are defined by using single quotes (apostrophes) around the character. An example of character declaration and initialization to a character constant is as follows:

Strings

C++ Declare A String

The lastve talked about string variables in relation to cout before, and as such you should know that string constants are defined by using double quotes. String variables are declared by using the string type, however as strings aren't actually 'primitive' types in C++ (and are instead defined by the standard library of stuff that comes bundled with C++), you are required to #include <string> to use thist strings aren't massively useful, but this is just because we don't really know how to utilize all the functionality of different data-types yet - for example, we don't know how to perform simple mathematics on number types, or how to check the value of booleans to change the logic of the program. All will be revealed in future tutorials.