Compilare: user.cpp: In function ‘int main()’: user.cpp:17:23: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(f[s1[i]] == 0) ^ user.cpp:18:24: warning: array subscript has type ‘char’ [-Wchar-subscripts] f[s1[i]] = s2[i]; ^ user.cpp:19:28: warning: array subscript has type ‘char’ [-Wchar-subscripts] else if(f[s1[i]] != s2[i]){printf("NU"); return 0;} ^ user.cpp:24:20: warning: NULL used in arithmetic [-Wpointer-arith] if(f[i] != NULL) printf("%c %c\n", i, f[i]); ^ user.cpp:9:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ceas2.in", "r", stdin); ^ user.cpp:10:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ceas2.out", "w", stdout); ^ user.cpp:11:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", s1); ^ user.cpp:12:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", s2); ^