comparing strings case insensitive 2

[titanandrews]

Actually this is a multi-part question. I am looking for a function in the string class to compare 2 strings and ignore case. In Java there is such a function, compareToIgnoreCase(), but I cannnot find anything in the standard library for C++. So I thought maybe there would be a toUpper() and toLower() function but I also cannot find these. Surely there are similar functions somewhere in the C++ standard libs. Can someone please point me the way. Many thanks to you!


Barry

 

[palbano]

>> in the standard library for C++.

If your referring to the runtime library there are:
int toupper(int)
int tolower(int)

So to use them to transform a string you must loop through the characters of the array.

If your referring to the Standard Template Library there is the transform algorithm

#include <string>
#include <algorithim>
#include <locale>
using namespace std;

string s(“Hello World!”);
transform(s.begin(), s.end(), s.begin(), tolower);
cout << s.c_str() << endl;

-pete
_{I just can't seem to get back my IntelliSense}

 

[PerFnurt]

If you want a string class with case insensitive comparisons, but with original case preserved you could do like this:

#include <string>

// char_traits for case-insensitive comparison
struct ci_char_traits : public std::char_traits<char>
{
static bool eq(char c1, char c2)
{
return toupper(c1) == toupper(c2);
}
static bool ne(char c1, char c2)
{
return toupper(c1) != toupper(c2);
}
static bool lt(char c1, char c2)
{
return toupper(c1) < toupper(c2);
}

static int compare(const char* s1, const char* s2, size_t n)
{
char ch1 = *s1++;
char ch2 = *s2++;

while(n>0 && eq(ch1,ch2))
{
n--;
ch1=*s1++;
ch2=*s2++;
}

return toupper(ch1)-toupper(ch2);
}

static const char* find(const char *s, int n, char a)
{
while(n-- > 0 && toupper(*s) != toupper(a))
{
++s;
}
return s;
}

};

// cistring is just a combination of basic_string and
// ci_char_traits
typedef std::basic_string<char, ci_char_traits, std::allocator<char> > cistring;


test()
{
cistring s1(&quot;abcd&quot;
cistring s2(&quot;AbCd&quot;

bool b;
b = s1 == s2; // true
s1.c_str(); //Returns &quot;abcd&quot;
s2.c_str(); //Returns &quot;AbCd&quot;

}
}

 

[apatterno]

One word:

_stricmp

Will

 

[palbano]

>> C++ standard libs

_stricmp

Will, isn't that a Microsoft extension and therefore not standard?

-pete
_{I just can't seem to get back my IntelliSense}

 

[apatterno]

I didn't think titanandrews was intending to limit himself to the standard CRT

 

[palbano]

Will,

boy your a slippery one eh?

Sorry that came across as questioning you... I really was looking for validation of my understanding of it.

-pete
_{I just can't seem to get back my IntelliSense}

 

[titanandrews]

So for platform independence, I should not use the runtime library?


Barry