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c++pointerspointer-arithmetic

In c++ using pointer arithmetic

How do you display the last character in a character array when you don't know how big the array is? Would array *('\0' - 1) work?

Solution

  • If a character array contains a C-style string, ie it contains a null terminator, then you can apply the standard C function strlen(), like this:

    char s[] = "Hello";
//...
size_t n = strlen( s );

if ( n != 0 ) std::cout << s[n-1] << '\n';

    Otherwise, you can write a template function like this:

    template <size_t N>
char last_char( const char ( &s )[N] )
{
    return s[N-1];
}

    and call it like this:

    char s[] = { 'H', 'e', 'l', 'l', 'o' };

std::cout << last_char( s ) << '\n';