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;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:9:11: warning: unused variable ‘x’ [-Wunused-variable] char x,s[200001],t[200001]; ^ user.cpp:12:23: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(t,200001,f); ^ user.cpp:16:23: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(s,200001,f); ^