Conversion of character string to integer (long long type) and storing pointer in last character string
long long strtoll(const char *str, char **ptr, int base);
Returns the converted value if the partial character string could be converted. If it could not, 0 is returned.
If an overflow occurs (the converted value is too larger), LLONG_MAX or LLONG_MIN is returned, and macro ERANGE is set to global variable errno.
This function is the same as strtol except that the type of the return value is of long long type.
The operation is undefined when the -Xansi option is specified.