C++: Replace character in a string with more than one number?

Question

I am currently trying to replace a single character in a string with more than one number. Lets make it quick:

replace(string.begin(), string.end(), 'a', '1');

^ WORKS! ^

replace(string.begin(), string.end(), 'a', '11');

or

replace(string.begin(), string.end(), 'a', "1");

^ DOESN'T WORK! ^

How do I do it? Is there any function for it?

NOTE: I'm not asking how to:

Replace part of a string with another string
Replace substring withanother substring

Aside: `'11'` is a multi-character-literal, having type `int`. It is most likely not remotely what you think it is. — Deduplicator, May 09 '14 at 13:18
And BTW, this question is not even a part of those 'already answered' questions! Can you people even read? — Marwan Ansari, May 09 '14 at 13:45

Vlad from Moscow · Accepted Answer · 2014-05-09T14:12:11.310

0

You should use some overloaded member function replace of class std::basic_string instead of the standard algorithm std::replace.

For example

for ( std::string::size_type pos = 0;
      ( pos = s.find( 'a', pos ) ) != std::string::npos;
      pos += 2 )
{
   s.replace( pos, 1, 2, '1' );
}

Or if the number can be any arbitrary string then you can write

std::string number( "123" );
for ( std::string::size_type pos = 0;
      ( pos = s.find( 'a', pos ) ) != std::string::npos;
      pos += number.size() )
{
   s.replace( pos, 1, number );
}

If you want to replace a number with a character then you can write

for ( std::string::size_type pos = 0;
      ( pos = s.find( "11", pos ) ) != std::string::npos;
      ++pos )
{
   s.replace( pos, 2, 1, 'a' );
}

edited May 09 '14 at 14:12

answered May 09 '14 at 13:25

Vlad from Moscow

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The first one works! Thanks alot man! :) – Marwan Ansari May 09 '14 at 13:37
Emm... how can I do it in reverse? Like number to alphabet? Example: 'a' to 123 then 123 to 'a'? – Marwan Ansari May 09 '14 at 14:02
Nevermind, I've figured it out. Thanks again :) – Marwan Ansari May 09 '14 at 14:06
@Marwan Ansari See my updated post. In general you should use together member functions find and replace of class std::string. – Vlad from Moscow May 09 '14 at 14:08

Appleshell · Answer 2 · 2014-05-09T13:26:22.730

-1

You need to give the same type of argument as the value to be replaced and the replacing value.

'a' is a char, while "1" is a string. You can't mix those two, replace in this case only supports chars.

Note: '11' is not a valid char.

edited May 09 '14 at 13:26

answered May 09 '14 at 13:15

Appleshell

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That explains why the OP's approach doesn't work. But he was asking for a way to achieve what he wants. – lethal-guitar May 09 '14 at 13:17
1

Regarding your edit: `'11'` might be valid for certain implementations. [See this question for example](http://stackoverflow.com/q/6944730/1451714). – lethal-guitar May 09 '14 at 13:18
@lethal-guitar It's of type `int` and not of type `char`. – Appleshell May 09 '14 at 13:25
@AdamS fair enough. Still, it will possibly compile without error. I'd add that it is a "multi-character literal". – lethal-guitar May 09 '14 at 13:27

C++: Replace character in a string with more than one number?

2 Answers2