Is there a TryParse equivalent in C++ (gcc)?

Question

Is there a equivalent of TryParse in C++(gcc) ?

I would like to parse a string which may contain (+31321) and store it as long. I know phone numbers are stored as st

Answer 1

the input extraction operator >> (i hope it's an acceptable name) applies and returns a stream&, that has a bool operator, meaning the extraction has been succesfully attempted. For instance, from the Cubbi answer:

...
    std::istringstream s("+31321");
    long n;
    if (s >> n)
      std::cout << n << '\n';
....

This will succed, of course, given the appropriate content of s.

Somewhat different (easier but not type safe) also the scanf family has practical tools available in c++ as well c. You could of course write the example this way:

...
    long n;
    if (sscanf("+31321", "%d", &n) == 1)
      std::cout << n << '\n';
...

A subset of regular expressions make this rather powerful: for instance to match a comma separed multi fields with left space trimming:

   if (sscanf("a,b,c", " [^,], [^,], [^,]", a,b,c) == 3) ...