Compilare: user.cpp: In function ‘int main()’: user.cpp:70:5: warning: ‘char* gets(char*)’ is deprecated [-Wdeprecated-declarations] gets(mat[i]+1); ^~~~ In file included from /usr/include/c++/6/cstdio:42:0, from user.cpp:1: /usr/include/stdio.h:638:14: note: declared here extern char *gets (char *__s) __wur __attribute_deprecated__; ^~~~ user.cpp:70:18: warning: ‘char* gets(char*)’ is deprecated [-Wdeprecated-declarations] gets(mat[i]+1); ^ In file included from /usr/include/c++/6/cstdio:42:0, from user.cpp:1: /usr/include/stdio.h:638:14: note: declared here extern char *gets (char *__s) __wur __attribute_deprecated__; ^~~~ user.cpp:61:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "rj.in", "r", stdin ); ^ user.cpp:62:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "rj.out", "w", stdout ); ^ user.cpp:66:28: 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:70:19: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(mat[i]+1); ^ /tmp/ccenHK44.o: In function `main': user.cpp:(.text.startup+0x97): warning: the `gets' function is dangerous and should not be used.