Trim a string

[Rope]

Hi I'm new to c++ and I'm trying to trim a string from all the spaces it has. But so far I've had no luck at all.

So this is an example string " bla bla bla bla "
This should be the output of the method "blablablabla".

Does anyone know how to do this?

Thanks in advance Rope.

[z05DSL3A]

std::remove(astring.begin(), astring.end(), ' ');

[Rope]

That doesn't work. leaves me with "test" but I entered "test test test". So it should be "testtesttest".

Any other ideas?

[z05DSL3A]

This code works for me:

#include <iostream>
#include <string>
#include <algorithm>

int main(void)
{
    std::string astring(" Test Test Test ");
    std::remove(astring.begin(), astring.end(), ' ');
    std::cout << astring << std::endl;
    return 0;
}

[Rope]

Does it also apply when using cin to give astring a value?
Because your right when I use it to plainly display the string when the value is already given.
But when I use it like this:

   string astring;
   cin >> astring;
   remove(astring.begin(), astring.end(), ' ');   
   cout << astring << endl;

It just cout's "test" so it does remove the ' ', but it also delete's the other parts of the string.

[gzero]

That's because cin stops reading at the " ", so the first "Test" is all that ever makes it into the string in the first place. Instead of cin, use getline:

#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

int main()
{
     string astring;
     getline(cin,astring);
     remove(astring.begin(),astring.end(),' ');
     cout<<astring<<endl;
     return 0;
}

The getline function generally works much better when dealing with strings.

[ropez]

@Rope: Try changing the second line to this:

getline(cin, astring);

[z05DSL3A]

Give this a blast:

#include <iostream>
#include <string>
#include <algorithm>

int main(void)
{
    std::string astring;
    std::cout << "Enter Text:=";
    std::cin >> astring;
    std::cout << "Before trim:=" << astring << std::endl;
    std::remove(astring.begin(), astring.end(), ' ');
    std::cout << "After trim:=" << astring << std::endl << std::endl;
    
    std::cin.clear();           //clear flags
    std::cin.ignore(256, '\n'); //dump input stream;

    std::string bstring;
    std::cout << "Enter Text (getline):=";
    std::getline(std::cin, bstring);
    std::cout << "Before trim:=" << bstring << std::endl;
    std::remove(bstring.begin(), bstring.end(), ' ');
    std::cout << "After trim:=" << bstring << std::endl;

    return 0;
}

[Rope]

Ok I tried to adjust the code to getlin(cin, astring). But nothing is happening.

code:

#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

int main()
{
     string astring;
     getline(cin,astring);
     remove(astring.begin(),astring.end(),' ');
     cout<<astring<<endl;
     return 0;
     system("pause");
}

I enter: "test test test"
The output: ziltch, nada, nothing

system("pause") is there because of windows.

This is just ridiculous. I know how to do the whole thing with classes in header files etc. But a simple thing like this just won't work.

@ Grey wolf Tried your solution to. Doesn't work for me. The program just exits doing nothing.

[z05DSL3A]

I have put your code into Dev-C++ and Visual Studio 2008 and it works in both (apart from system("pause") needs to be before return 0)!

What IDE/compiler are you using?

[Rope]

@ grey wolf. Well. That did the trick. I relocated system("pause") above return 0; and now it works.

Thanks for the help!

P.S. Using Dev- C++

[guruplus]

Hello,
Use this macro

#define CHARRTRIM(__x_) {int i; for (i=strlen(__x_) - 1; (i>=0)&&(__x_[i]==' '); i--); __x_[i + 1]=0;}; 

[guruplus]

Hello,
Use this macro

#define CHARRTRIM(__x_) {int i; for (i=strlen(__x_) - 1; (i>=0)&&(__x_[i]==' '); i--); __x_[i + 1]=0;}; 

[z05DSL3A]

SteakRider
That does not do what was asked for! AND it's a macro

TO_PUT_IT_BLUNTLY: Macros are the bluntest instrument of C and C++'s abstraction
facilities, ravenous wolves in functions' clothing, hars to tame, marching to their
own beat all over your scopes. Aviod them.
                                                                            Item 16 C++ Coding Standards
                                                                            Herb Sutter, Andrei Alexandrescu