Compilare: user.cpp: In function ‘void back(long long unsigned int, long long unsigned int)’: user.cpp:16:4: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(k<=18) ^ user.cpp: In function ‘int main()’: user.cpp:33:21: warning: format ‘%u’ expects argument of type ‘unsigned int*’, but argument 2 has type ‘long long unsigned int*’ [-Wformat=] scanf("%ul%ul",&a,&b); ^ user.cpp:33:21: warning: format ‘%u’ expects argument of type ‘unsigned int*’, but argument 3 has type ‘long long unsigned int*’ [-Wformat=] user.cpp:37:17: warning: format ‘%u’ expects argument of type ‘unsigned int’, but argument 2 has type ‘long long unsigned int’ [-Wformat=] printf("%ul",max); ^ user.cpp:31:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("multiplu.out","w",stdout); ^ user.cpp:32:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("multiplu.in","r",stdin); ^ user.cpp:33:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ul%ul",&a,&b); ^