C언어. 포인터, 할당, gets()

C++로 예전에 맹글었던겁니다. reverse함수는 일반적인 루틴을 따른겁니다.
han_reverse는 심심해서리...-.-;;

#include <iostream>
using namespace std;

char* reverse(char* s)
{
		if(s == 0) return 0;
		int len = strlen(s);
		int count = len / 2;
		char c;

		for(int i = 0; i < count; i++){
				c = s[i];
				s[i] = s[len - 1 - i];
				s[len - 1 - i] = c;
		}
		return s;
}

char* han_reverse(char* s)
{
		if(s == 0) return 0;
		int len = strlen(s);
		char fc, sc; // first char, second char
		int i, j;

		for(i = 0, j = len - 1; i < j; i++, j--){
				if(s[i] < 0){ // if hangul
						if(s[j] < 0){ // if hangul
								fc = s[j - 1];
								sc = s[j];
								s[j - 1] = s[i];
								s[j] = s[i + 1];
								s[i] = fc;
								s[i + 1] = sc;
								i++; // because hangul 
						}else{
								fc = s[i];
								sc = s[i + 1];
								s[i] = s[j];
								for(int n = i + 1; n < j - 1; n++){
										s[n] = s[n + 1];
								}
								s[j - 1] = fc;
								s[j] = sc;
						}
						j--; // because hangul
				}else{
						if(s[j] < 0){ // if hangul
								fc = s[j - 1];
								sc = s[j];
								s[j] = s[i];
								for(int n = j - 1; n > i + 1; n--){
										s[n] = s[n - 1];
								}
								s[i + 1] = sc;
								s[i] = fc;
								i++; // because hangul
						}else{
								fc = s[i];
								s[i] = s[j];
								s[j] = fc;
						}
				}
		}
		return s;
}


int main(int argc, char *argv[])
{
		char buffer[BUFSIZ];
		int h_mode = 0; // hangul mode off

		if(argc == 2){
				if(strcmp(argv[1], "-H") == 0){
						h_mode = 1; // hangul mode on
				}
		}

		do{
				cout << "INPUT>";
				cin.getline(buffer, BUFSIZ);
				if(strncmp(buffer, "exit", 4) == 0) break;
				if(h_mode) han_reverse(buffer);
				else reverse(buffer);
				cout << buffer << endl;
		}while(1);
		return 0;
}