Compilare: user.cpp: In function ‘int main()’: user.cpp:20:19: warning: format ‘%s’ expects argument of type ‘char*’, but argument 2 has type ‘char (*)[2000001]’ [-Wformat=] scanf("%s", &a); ^ user.cpp:21:19: warning: format ‘%s’ expects argument of type ‘char*’, but argument 2 has type ‘char (*)[2000001]’ [-Wformat=] scanf("%s", &b); ^ user.cpp:36:36: warning: NULL used in arithmetic [-Wpointer-arith] for(int i = sizeA - 1; b[i] != NULL; ++i) ^~~~ user.cpp:61:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < ans.size() && i < 1000; ++i) ~~^~~~~~~~~~~~ user.cpp:17:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("strmatch.in", "r", stdin); ^ user.cpp:18:41: 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); ^ user.cpp:20:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", &a); ^ user.cpp:21:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", &b); ^