Question

My string is std::string str ("DDWD");

I want to change the corresponding to the following

D = [0-9] W = [a-z]

soo…("[0-9][0-9][A-Z][0-9]")

The replace method does not seem to accomade this, so i tried something like

string tmp = "DDDWD";   
int len = 0;   
len = tmp.length();   
for( int i = 0; i < len; i++ )
{
    if ( tmp[i] == 'D')
    {  
        tmp.replace(i,1,"[0-9]");  
        i+=2;  
    }
} 

However trying to change both letters D and W there was a problem and it wasent changing them all correctly?

Does anyone know a way how to change each letter at the same time to the corresponding string above?

Thankful for any help

Answer 1

I think this would be cleaner if you used a separate string:

string tmp = "DDDWD";
string tmp2;

for (int i=0; i<tmp.size(); ++i)
{
    if (tmp[i] == 'D')
        tmp2 += "[0-9]";
    else if (tmp[i] == 'W')
        tmp2 += "[a-z]";
    else
        tmp2 += tmp[i];
}

tmp.swap(tmp2);

// or in C++11
// tmp = std::move(tmp2);