Compilare: user.cpp: In function ‘void read()’: user.cpp:21:5: warning: ‘char* gets(char*)’ is deprecated [-Wdeprecated-declarations] gets(ln); ^~~~ In file included from user.cpp:1:0: /usr/include/stdio.h:638:14: note: declared here extern char *gets (char *__s) __wur __attribute_deprecated__; ^~~~ user.cpp:21:12: warning: ‘char* gets(char*)’ is deprecated [-Wdeprecated-declarations] gets(ln); ^ In file included from user.cpp:1:0: /usr/include/stdio.h:638:14: note: declared here extern char *gets (char *__s) __wur __attribute_deprecated__; ^~~~ user.cpp:23:25: warning: NULL used in arithmetic [-Wpointer-arith] for(i = 0; ln[i] != NULL; ++ i) ^~~~ user.cpp:19:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d\n", &n, &d); ^ user.cpp:21:13: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(ln); ^ user.cpp: In function ‘int main()’: user.cpp:44:44: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("slidingwindow.in", "r", stdin); ^ user.cpp:45:46: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("slidingwindow.out", "w", stdout); ^ /tmp/ccpqbhYZ.o: In function `read()': user.cpp:(.text+0x21): warning: the `gets' function is dangerous and should not be used.