CODEWITHSUNDEEP
c++c++11
user11779843
user11779843

Reputation:

C++ Error: no matching function for call to 'toupper'

The following code raises the no matching function for call to 'toupper' error (C++ 11):

string s("some string");
if (s.begin() != s.end())
{
    auto it = s.begin();
    it=toupper(it);
}

This code is from C++ primer, fifth edition, chapter 3, about "introducing iterators".

Do you know why this error?

Upvotes: 0

Views: 4353

Answers (1)

einpoklum
einpoklum

Reputation: 131978

  1. You need to include the appropriate headers, in this case <string> and <cctype>.
  2. You need to specify the namespaces, in this case std:: (use say using namespace std, but that is not a good idea).
  3. it is not a character. It is an iterator into the string. Think of it as a pointer-like object. When you want to change a character pointed to by p, you would say *p = do_something_with(*p), not p = do_something_with(p) which would change the pointer.

Thus if we write:

#include <iostream>
#include <cctype>

int main()
{
    std::string s("some string");
    if (s.begin() != s.end()) {
        auto it = s.begin();
        *it = std::toupper(*it);
    }
}

then this compiles (GodBolt.org).

Upvotes: 1

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