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Using string as char array

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Using string as char array

 
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  #1
Dec 2nd, 2008
How would I delete one char from a string?

C++ Syntax (Toggle Plain Text) 
  1. string aWord = "question?";
  2.  
  3. while(aWord[i])
  4. 	{
  5. 	if(isalpha(aWord[i]))printf ("character %c is alphabetic\n",aWord[i]);
  6. 	else
  7. 		delete[i]aWord;
  8.     i++;
  9.   }
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Re: Using string as char array

 
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  #2
Dec 2nd, 2008
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Originally Posted by JackDurden View Post
How would I delete one char from a string?

C++ Syntax (Toggle Plain Text) 
  1. string aWord = "question?";
  2.  
  3. while(aWord[i])
  4. 	{
  5. 	if(isalpha(aWord[i]))printf ("character %c is alphabetic\n",aWord[i]);
  6. 	else
  7. 		delete[i]aWord;
  8.     i++;
  9.   }
Use the replace function from string:

http://www.cplusplus.com/reference/s...g/replace.html

C++ Syntax (Toggle Plain Text) 
  1. string aWord = "abcdef";
  2. aWord.replace (3, 1, "");

aWord now contains "abcef";

Edit: Or just use erase:
C++ Syntax (Toggle Plain Text) 
  1. aWord.erase (3, 1);

Has the same effect.
Last edited by VernonDozier; Dec 2nd, 2008 at 3:45 pm.
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Re: Using string as char array

 
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  #3
Dec 2nd, 2008
Note you can use find() or find_first_of() etc to get the index of the character youare after.

Chris
Knowledge is power -- But experience is everything
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Re: Using string as char array

 
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  #4
Dec 2nd, 2008
Well that sort of works but if the char I want to delete/erase is at the end of the string my compiler crashes. I dont understand how to delete/erase a char that is not an alphanumeric type.

C++ Syntax (Toggle Plain Text) 
  1.   int i=0;
  2.  string aWord = "abcdf!";
  3.  
  4. while(aWord[i])
  5. 	{
  6. 	if(isalpha(aWord[i]))printf ("character %c is alphabetic\n",aWord[i]);
  7. 	else
  8. 		aWord.erase (i, 1);
  9.     i++;
  10.   }
  11.   cout<<aWord;
Last edited by JackDurden; Dec 2nd, 2008 at 3:56 pm.
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Re: Using string as char array

 
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  #5
Dec 2nd, 2008
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Originally Posted by JackDurden View Post
How would I delete one char from a string?

C++ Syntax (Toggle Plain Text) 
  1. string aWord = "question?";
  2.  
  3. while(aWord[i])
  4. 	{
  5. 	if(isalpha(aWord[i]))printf ("character %c is alphabetic\n",aWord[i]);
  6. 	else
  7. 		delete[i]aWord;
  8.     i++;
  9.   }
I can give you two ways. one through STL & other through using the strings only

cpp Syntax (Toggle Plain Text) 
  1.        string strWord = "Hello, World!";
  2. 	string strResult = "";
  3.  
  4. 	for(size_t idx = 0; idx < strWord.size(); ++idx) {
  5. 		if (isalpha(strWord[idx])) {
  6. 			strResult += strWord[idx];
  7. 		}
  8. 	}
  9. 	cout<< strResult<<endl;

Another Way
cpp Syntax (Toggle Plain Text) 
  1.   string strWord = "Hello, World! Laiq?";
  2. 	size_t pos = 0;
  3.  
  4. 	for(size_t idx = 0; idx < strWord.size(); ++idx) {
  5. 		if (isalpha(strWord[idx])) {
  6. 			strWord[pos] = strWord[idx];
  7. 			++pos;
  8. 		}
  9. 	}
  10. 	strWord.resize(pos);
  11.  
  12. 	cout<< strWord <<endl;

Little more tricky.
cpp Syntax (Toggle Plain Text) 
  1.    Check the remove_if (...)

Hope the above techniques might help you in understanding ?
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Re: Using string as char array

 
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  #6
Dec 2nd, 2008
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Originally Posted by JackDurden View Post
Well that sort of works but if the char I want to delete/erase is at the end of the string my compiler crashes. I dont understand how to delete/erase a char that is not an alphanumeric type.

C++ Syntax (Toggle Plain Text) 
  1.   int i=0;
  2.  string aWord = "abcdf!";
  3.  
  4. while(aWord[i])
  5. 	{
  6. 	if(isalpha(aWord[i]))printf ("character %c is alphabetic\n",aWord[i]);
  7. 	else
  8. 		aWord.erase (i, 1);
  9.     i++;
  10.   }
  11.   cout<<aWord;
Your program ran for me. I don't know what error you got, but if it is an index-out-of-range/segmentation fault error, you may want to change this:
C++ Syntax (Toggle Plain Text) 
  1. while (aWord[i])

to

C++ Syntax (Toggle Plain Text) 
  1. while (i < aWord.length ())

That might make a difference, might not. As to your other problem, only increment i if aWord[i] is a letter. erase and replace will cause the indexes to change, so some characters will be skipped if you use erase/replace AND increment i.
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Re: Using string as char array

 
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  #7
Dec 2nd, 2008
Check the size..
C++ Syntax (Toggle Plain Text) 
  1.  
  2. int i=0;
  3. string aWord = "abcdf!";
  4.  
  5. while(aWord[i])
  6. {
  7.    if(isalpha(aWord[i]))
  8.       printf ("character %c is alphabetic\n",aWord[i]);
  9.    else
  10.    {
  11. 	aWord.erase (i, 1);
  12.       //..Is idx > length
  13.        if(i>aWord.size())
  14.           break;
  15.        i--;
  16.    }
  17.    i++;
  18. }
  19. cout<<aWord;
Last edited by cikara21; Dec 2nd, 2008 at 5:34 pm.
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