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[joeshmo]

joeshmo

C++ strings?

How can I declare a string in c++? I want to do something like

waste=new int[50000]

exept with a string, like

waste=new string[500000]

Any help? Thanks.

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[Ben]

Ben

Re: C++ strings?

There are two ways, one is the C way of using char arrays, and the other is the C++ way of using a string class.
A char array is simply just the same as int[5000] but char[5000] and the 5000 is how many characteres that are in it.
Though that's really silly because it just uses a quarter of the memory an int does.
I really don't see what the point of your string is :-p

But if you want to use strings then go here:
http://www.cppreference.com/cppstring/index.html

Very useful if you can fathom it. Oh and btw c libraries like iostream use c strings (character arrays) and you can get one of these from a string class by using like
string.c_str(). That turns the contents of a string into a char array.

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[joeshmo]

joeshmo

Re: C++ strings?

Hmm. Thanks.

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[Infinitus]

Infinitus

Re: C++ strings?

I tend to just use char pointers, its not the best way or the easiest to do modification on the string, but its simpler to declare and use.

you can declare char array like so;

Code: [Select]

char* MyString;
MyString = "Hello World";


[joeshmo]

joeshmo

Re: C++ strings?

I tend to just use char pointers, its not the best way or the easiest to do modification on the string, but its simpler to declare and use.

you can declare char array like so;

Code: [Select]

char* MyString;
MyString = "Hello World";


whats the difference in doing this and just declaring it as
char mystring?

• 

[Infinitus]

Infinitus

Re: C++ strings?

I tend to just use char pointers, its not the best way or the easiest to do modification on the string, but its simpler to declare and use.

you can declare char array like so;

Code: [Select]

char* MyString;
MyString = "Hello World";


whats the difference in doing this and just declaring it as
char mystring?

Put simply, char mystring would only be able to hold 1 character, char* mystring can hold as many as you want.

[therabidwombat]

therabidwombat

Re: C++ strings?

char mystring would just be a single character. However, an array is a pointer to the head of the array, and a char pointer works essentially the same way as a char array.

If you're using C++.net, there's a managed String class, but it's really tough to work with (I've used strings in probably a dozen languages and only that one has confused me ), but it has a lot of functions too, so supposedly it's useful.

• 

[Max]

Max

Re: C++ strings?

char mystring creates a single character variable. char *mystring creates a pointer to a character.  Since all arrays are are contigious memory spaces holding the same type of data (char array, int array), and the first entry in the array is denoted by the memory address of the variable name, you create a string(an array of characters ending in a '\0') via creating a pointer to the first element in the string.  For instance: you create an array char a[512], using the variable a gives you the memory address of the first part of the array, you can call a[0], by using *a.  Similarly char *a will do the same thing, except you are not defining the maximum amount of chars the array can hold.  Each have their own uses for creating a string.

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[aab]

aab

Re: C++ strings?

the std::string is quite easy to use, and compatible with things like std::stringstream (#include<sstream>) and the ios classes, making it nice and easy to use.
eg:

Code: [Select]

std::string myName = "aab",myDetails;
std::stringstream ss;

if( myName == "aab" )
{
ss<< "my name is: " << myName << ", and my age is: " << 18 ;
myDetails = ss.str();
std::cout<< myDetails << std::endl;
}


for  // loop through with an iterator: same syntax as many standard objects: efficient: iterator is really a pointer, so this is like having a char [] and looping from char [0] to the last one, but safer and faster, though you could just use a char* and use ++ on it the same way
(
std::string::iterator
i = myDetails.begin();
i != myDetails.end();
++i
)
{
*i = 'A';
}

std::cout<< myDetails << std::endl;


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[joeshmo]

joeshmo

Re: C++ strings?

String functions are included in Iostream?

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[aab]

aab

Re: C++ strings?

cstring for string
sstream for stringstream

I ♥ Sol
.... I ♥ Sol ? wtf how long has that been there? >_> *rrrrrrrrar*

•