Swap first and last letters in word

#include <iostream>

using namespace std;

void SwapChars(char *str, char *delim)
{
    size_t length = strlen(str);
    size_t variants = strlen(delim);
    int last = length;
    while(length--)
    {
        bool delimited = false;
        for (unsigned int i = 0; i < variants; ++i)
        if (str[length] == delim[i])
        {
            delimited = true;
            break;
            }
        if (delimited || length == 0)
        {
            if (last - length < 3)
            {
                last = length;
                continue;
            }
            else
            {
                int pos = (length) ? length+1 : 0;
                char buf = str[last-1];
                str[last-1] = str[pos];
                str[pos] = buf;
                last = length;
            }
        }
    }
}
int main()
{
    char str[] = "ENGLISH, MOTHERFUCKER! DO-YOU-SPEAK-IT?";
    char delim[] = " -!,?";
    SwapChars(str, delim);
    printf("%s\n", str);
    system("pause");
    return 0;
}