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Apr 10, 2017 There are many ways to create strings in C. The examples used in this section are from C Primer (5th Edition). Although it is quite a thick book, C primer is a great resource for those that are willing to fork in the time and effort to sift through its contents. C program to Reverse a String - Reverse of String means reverse the position of all character of any String. For example reverse of porter is retrop. Tutorials, Free Online Tutorials, sitesbay provides tutorials and interview questions of all technology like java tutorial, android, java frameworks, javascript, ajax, core java, sql, python.
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C++ provides following two types of string representations −
- The C-style character string.
- The string class type introduced with Standard C++.
The C-Style Character String
The C-style character string originated within the C language and continues to be supported within C++. This string is actually a one-dimensional array of characters which is terminated by a null character '0'. Thus a null-terminated string contains the characters that comprise the string followed by a null.
The following declaration and initialization create a string consisting of the word 'Hello'. To hold the null character at the end of the array, the size of the character array containing the string is one more than the number of characters in the word 'Hello.'
If you follow the rule of array initialization, then you can write the above statement as follows −
Following is the memory presentation of above defined string in C/C++ −
Actually, you do not place the null character at the end of a string constant. The C++ compiler automatically places the '0' at the end of the string when it initializes the array. Let us try to print above-mentioned string −
When the above code is compiled and executed, it produces the following result −
![Dev C++ Strings Dev C++ Strings](https://i.ytimg.com/vi/VH0EYI6tv4Y/maxresdefault.jpg)
C++ supports a wide range of functions that manipulate null-terminated strings −
Sr.No | Function & Purpose |
---|---|
1 | strcpy(s1, s2); Copies string s2 into string s1. |
2 | strcat(s1, s2); Concatenates string s2 onto the end of string s1. |
3 | strlen(s1); Returns the length of string s1. |
4 | strcmp(s1, s2); Returns 0 if s1 and s2 are the same; less than 0 if s1<s2; greater than 0 if s1>s2. |
5 | strchr(s1, ch); Returns a pointer to the first occurrence of character ch in string s1. |
6 | strstr(s1, s2); Returns a pointer to the first occurrence of string s2 in string s1. |
Following example makes use of few of the above-mentioned functions −
C# String Examples
When the above code is compiled and executed, it produces result something as follows −
The String Class in C++
The standard C++ library provides a string class type that supports all the operations mentioned above, additionally much more functionality. Let us check the following example −
When the above code is compiled and executed, it produces result something 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:
![Dev c++ program download Dev c++ program download](https://i.ytimg.com/vi/MaECx_jYcSU/maxresdefault.jpg)
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 https://ablerenew176.weebly.com/blog/guitar-rig-vst-crack. 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.Dev C++ 5.11
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:Dev C++ Download Windows 10
Strings
Dev C++ 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.