c++ get the last (n) char in a string

Question

i have a string and i want to get, for example, the position of the last (.) in the string, or whatever char i want to check, but untill now i just get a headeach.

thanks

Answer 1

string lastN(string input)
{
     return input.substr(input.size() - n);
}

Answer 2

Is find_last_of what you need?

size_type find_last_of( const basic_string& str, size_type pos = npos ) const;

Finds the last character equal to one of characters in the given character sequence. Search finishes at pos, i.e. only the substring [0, pos] is considered in the search. If npos is passed as pos whole string will be searched.

Answer 3

If your string is a char array:

#include <cstdio>
#include <cstring>

int main(int argc, char** argv)
{
 char buf[32] = "my.little.example.string";
 char* lastDot = strrchr(buf, '.');
 printf("Position of last dot in string: %i", lastDot - buf);
 return 0;
}

..or a std::string:

#include <cstdio>
#include <string>

int main(int argc, char** argv)
{
 std::string str = "my.little.example.string";
 printf("Position of last dot in string: %i", str.find_last_of('.'));
 return 0;
}

Answer 4

   #include <string>
    /**
    * return the last n characters of a string,
    * unless n >= length of the input or n <= 0, in which case return ""
    */
    string lastN(string input, int n)
    {
        int inputSize = input.size();
        return (n > 0 && inputSize > n) ? input.substr(inputSize - n) : "";
    }