tolower

The below code snippet is used to convert a string to lower case. int main() { unsigned char s[] = "AbS.d_"; tolower(s); printf("%s\n", s); return 0; } I am getting the output as: AbS.d_ Why the string is not being converted? tolower takes int and return lowered int. This should work: int i=0; for(i=0; s[i]; i++) { s[i]=tolower(s[i]); } tolower takes a character type as parameter, but you use a string. You need to run through your array, and call tolower for each character. 来源： https://stackoverflow.com/questions/12145463/tolower-not-working

I am supposed to ask the user for two file names (input and output files). The contents from the input file should be read and the first letter of each sentence should be made uppercase while every other letter should be made lowercase. The results should then be stored in the output file. I am aware that there are ways of using the toupper and tolower functions that include pointers, arrays, or even ASCII values of chars but I am trying to get this code to work by using if/else and while statements, as well as boolean statements. I have had various results ranging from all the letters being

I have read that when in your application you do a lot of string comparison and using ToLower method, this method is quite costly. I was wondering of anyone could explain to me how is it costly. Would appreciate any info or explanation. Thanks! 500 - Internal Server Error It's costly because a new string is "manufactured". Compare that to calling, say, Equals with an overload that asks for a case-insensitive comparison. This allows the comparison to terminate, without having to create a new string, as soon as a mismatch is identified. See also writing culture-safe managed code for a very good

Is there an inbuilt function to convert C++ string from upper case letters to lowercase letters ? If not converting it to cstring and using tolower on each char is the only option ? Thank you very much in advance. If boost is an option: #include <boost/algorithm/string.hpp> std::string str = "wHatEver"; boost::to_lower(str); Otherwise, you may use std::transform : std::string str = "wHatEver"; std::transform(str.begin(), str.end(), str.begin(), ::tolower); You can also use another function if you have some custom locale-aware tolower . TortoiseTNT std::transform(myString.begin(), myString.end(

Given string foo , I've written answers on how to use cctype 's tolower to convert the characters to lowercase transform(cbegin(foo), cend(foo), begin(foo), static_cast<int (*)(int)>(tolower)) But I've begun to consider locale 's tolower , which could be used like this: use_facet<ctype<char>>(cout.getloc()).tolower(data(foo), next(data(foo), foo.size())); Is there a reason to prefer one of these over the other? Does their functionality differ at all? I mean other than the fact that tolower accepts and returns an int which I assume is just some antiquated C stuff? Unfortunately,both are equally

In C, strings are arrays of char ( char * ) and characters are usually stored in char . I noticed that some functions from the libC are taking as argument integers instead of a char. For instance, let's take the functions toupper() and tolower() that both use int . The man page says: If c is not an unsigned char value, or EOF, the behavior of these functions is undefined. My guess is that with a int , toupper and tolower are able to deal with unsigned char and EOF . But in fact EOF is in practice (is there any rule about its value?) a value that can be stored with a char , and since those