Algorithm for character replacement in string

[Old Wolf]

I have two strings of corresponding characters, for example:
s1 = "abc"
s2 = "XYZ"

Is there an algorithm so that whenever a character from S1 occurs
in a string, it is replaced by the corresponding character from S2?

eg. running "crabs" through this function will producs "ZrXYs".

[Victor Bazarov]

Old Wolf wrote:

I have two strings of corresponding characters, for example:
s1 = "abc"
s2 = "XYZ"

Is there an algorithm so that whenever a character from S1 occurs
in a string, it is replaced by the corresponding character from S2?

eg. running "crabs" through this function will producs "ZrXYs".

Do you mean, as a single function call, in the Standard library? No.

V
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[Frederick Gotham]

Old Wolf posted:

I have two strings of corresponding characters, for example:
s1 = "abc"
s2 = "XYZ"

Is there an algorithm so that whenever a character from S1 occurs
in a string, it is replaced by the corresponding character from S2?

eg. running "crabs" through this function will producs "ZrXYs".

I'm doing this just for the fun of it. If it's your homework, then in the
long run, you won't gain from copy-pasting my code... all it takes is one
exam to demonstrate your inability.
#include <cassert>

#ifndef NDEBUG

#include <cstring>

#endif

void SmartReplace( char *p,
const char * const check_for,
const char * const replace_with )
{

assert( std::strlen(replace_with) >= std::strlen(check_for) );

for( ; *p; ++p )
{
const char *p_check = check_for;
const char *p_replace = replace_with;

for( ; *p_check; ++p_check, ++p_replace )
{
if ( *p == *p_check ) *p = *p_replace;
}
}
}

#include <iostream>

#include <cstdlib>

int main()
{
using std::cout;

char str[] = "crabs";

SmartReplace( str, "abc", "XYZ" );

cout << str << '\n';

std::system("PAUSE");
}
--

Frederick Gotham

[Alf P. Steinbach]

* Old Wolf:

I have two strings of corresponding characters, for example:
s1 = "abc"
s2 = "XYZ"

Is there an algorithm so that whenever a character from S1 occurs
in a string, it is replaced by the corresponding character from S2?

eg. running "crabs" through this function will producs "ZrXYs".

On a system where char is 8-bit or thereabouts, use an array of all
possible character values as indices, with replacements as values. For
a more portable solution use a std::map<char,char>. Then apply
std::transform, or just use a for loop.

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