Compilare: user.cpp: In function ‘int main()’: user.cpp:54:13: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] chr = NULL; ^ user.cpp:60:33: warning: too many arguments for format [-Wformat-extra-args] scanf("%c", &chr, &x); ^ user.cpp:45:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("placare.in","r",stdin); ^ user.cpp:46:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("placare.out","w",stdout); ^ user.cpp:48:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &N, &M); ^ user.cpp:57:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); ^ user.cpp:60:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c", &chr, &x); ^