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Aug 27th, 2007

How to clear a string

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How do you clear a string in a single statement ?
for egs. i want to clear name[20] of all its contents and leave it completely empty

Please help

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joydsouza90

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Aug 27th, 2007

Re: How to clear a string

Click to Expand / Collapse Quote originally posted by joydsouza90 ...

How do you clear a string in a single statement ?
for egs. i want to clear name[20] of all its contents and leave it completely empty

Please help

c++ Syntax (Toggle Plain Text)
  const char *str="SpS";
  cout << str;
  str = NULL;
  const char *str="SpS";
  cout << str;
  str = NULL;

Last edited by SpS; Aug 27th, 2007 at 12:24 pm.

SpS

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Aug 27th, 2007

Re: How to clear a string

It's a character string? Just set the first character to be a terminator and it'll be treated as "".

C++ Syntax (Toggle Plain Text)
name[0] = '\0';
name[0] = '\0';

If it's a C++ string you can call the clear method and that truncates the string to be "".

C++ Syntax (Toggle Plain Text)
name.clear();
name.clear();

Hamrick

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Aug 27th, 2007

Re: How to clear a string

Are you talking about C++ strings or C-style char arrays? (I assume you're talking about char arrays, based on your post)

What do you mean by "completely empty"?

You can make a C++ string blank by doing this

CPP Syntax (Toggle Plain Text)
std::string name = "hello";
std::cout << name;
 
//Assign 'name' a blank string
name = ""; 
std::cout << name;
std::string name = "hello";
std::cout << name;

//Assign 'name' a blank string
name = ""; 
std::cout << name;

for a C-style char array, you could do this

CPP Syntax (Toggle Plain Text)
char name[20] = "fred";
std::cout << name;
 
//If the first character is a null terminator, the string is 'empty'.
name[0] = '\0' ;
std::cout << name;
char name[20] = "fred";
std::cout << name;

//If the first character is a null terminator, the string is 'empty'.
name[0] = '\0' ;
std::cout << name;

Or do you wish to iterate through every element and set each one to zero? (You can do that with a loop, although there's not much point.)

Bench

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Aug 27th, 2007

Re: How to clear a string

im using turbo c++
and none of the methods that u guys have mentioned seem to work

name[20] is a character array

joydsouza90

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Aug 27th, 2007

Re: How to clear a string

Please post the code you have so far...

iamthwee

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Aug 27th, 2007

Re: How to clear a string

Okay then, what are you doing exactly?

Hamrick

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Aug 27th, 2007

Re: How to clear a string

Click to Expand / Collapse Quote originally posted by joydsouza90 ...

How do you clear a string in a single statement ?
for egs. i want to clear name[20] of all its contents and leave it completely empty

C++ Syntax (Toggle Plain Text)
   char name[20];
   memset(name, 0, sizeof name);
   char name[20];
   memset(name, 0, sizeof name);

Although typically clearing all elements of a string is unnecessary.

Dave Sinkula

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Aug 27th, 2007

Re: How to clear a string

thanx a lot !!!

memset works .

joydsouza90

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Aug 27th, 2007

Re: How to clear a string

You should have posted the code for the others you have tried and the error messages or problems you encountered. The problem is unlikely to be with their code but rather how you typed it in or if you're using the outdated version of turbo c, which is probably very likely

Last edited by iamthwee; Aug 27th, 2007 at 2:26 pm.

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