Compilare: user.cpp: In function ‘void prefix()’: user.cpp:31:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=2;i<strlen(s1);i++) ^ user.cpp: In function ‘void kmp()’: user.cpp:47:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(s1[j]==s2[i] && j<=strlen(s1)) ^ user.cpp:49:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(j>strlen(s1)-1) ^ user.cpp: In function ‘int main()’: user.cpp:72:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<sol.size();i++) ^ user.cpp:70:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("strmatch.out","w",stdout); ^