Compilare: user.cpp: In function ‘int check_palindrom(char*, int*)’: user.cpp:13:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < strlen(a); i++) ^ user.cpp: In function ‘int arrange_palindrome(char*, int*)’: user.cpp:47:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(k != strlen(a) - l - 1){ ^