Convert a String In C++ To Upper Case

Question

How could one convert a string to upper case. The examples I have found from googling only have to deal with chars.

Answer 1

The faster one if you use only ASCII characters:

for(i=0;str[i]!=0;i++)
  if(str[i]<='z' && str[i]>='a')
    str[i]+='A'-'a';

Please note that this code run faster but only works on ASCII and is not an "abstract" solution.

Extended version for other UTF8 alphabets:

...
if(str[i]<='z' && str[i]>='a') //is latin
    str[i]+='A'-'a';
else if(str[i]<='я' && str[i]>='а') //cyrillic
    str[i]+='Я'-'я'
else if(str[i]<='ω' && str[i]>='α') //greek
    str[i]+='Ω'-'ω'
//etc...

If you need full UNICODE solutions or more conventional and abstract solutions, go for other answers and work with methods of C++ strings.