Compilare: user.cpp: In function ‘int main()’: user.cpp:13:20: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] t[strlen(t)-1]=NULL; ^ user.cpp:17:20: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s[strlen(s)-1]=NULL; ^ user.cpp:19:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<=strlen(s)-strlen(t)+1 && nr<=1000;i++) ^ user.cpp:21:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<=strlen(t)-1 && ok==1;j++) ^ user.cpp:9:12: warning: unused variable ‘x’ [-Wunused-variable] char x,s[2000001],t[2000001]; ^ user.cpp:12:25: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(t,20000001,f); ^ user.cpp:16:25: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(s,20000001,f); ^ In file included from /usr/include/stdio.h:934:0, from /usr/include/c++/4.8/cstdio:42, from /usr/include/c++/4.8/ext/string_conversions.h:43, from /usr/include/c++/4.8/bits/basic_string.h:2815, from /usr/include/c++/4.8/string:52, from /usr/include/c++/4.8/bits/locale_classes.h:40, from /usr/include/c++/4.8/bits/ios_base.h:41, from /usr/include/c++/4.8/ios:42, from /usr/include/c++/4.8/ostream:38, from /usr/include/c++/4.8/iostream:39, from user.cpp:1: In function ‘char* fgets(char*, int, FILE*)’, inlined from ‘int main()’ at user.cpp:12:25: /usr/include/i386-linux-gnu/bits/stdio2.h:253:58: warning: call to ‘__fgets_chk_warn’ declared with attribute warning: fgets called with bigger size than length of destination buffer [enabled by default] return __fgets_chk_warn (__s, __bos (__s), __n, __stream); ^ In function ‘char* fgets(char*, int, FILE*)’, inlined from ‘int main()’ at user.cpp:16:25: /usr/include/i386-linux-gnu/bits/stdio2.h:253:58: warning: call to ‘__fgets_chk_warn’ declared with attribute warning: fgets called with bigger size than length of destination buffer [enabled by default] return __fgets_chk_warn (__s, __bos (__s), __n, __stream); ^