Compilare: user.cpp: In function ‘int main()’: user.cpp:42:17: warning: array subscript has type ‘char’ [-Wchar-subscripts] a=(s2[v1][j]+j*( s1[v1][b-1]-s1[v1][j] ) ) %mod; ^ user.cpp:42:33: warning: array subscript has type ‘char’ [-Wchar-subscripts] a=(s2[v1][j]+j*( s1[v1][b-1]-s1[v1][j] ) ) %mod; ^ user.cpp:42:45: warning: array subscript has type ‘char’ [-Wchar-subscripts] a=(s2[v1][j]+j*( s1[v1][b-1]-s1[v1][j] ) ) %mod; ^ user.cpp:48:18: warning: array subscript has type ‘char’ [-Wchar-subscripts] s1[v2][j]=s1[v2][j-1]+a; ^ user.cpp:48:28: warning: array subscript has type ‘char’ [-Wchar-subscripts] s1[v2][j]=s1[v2][j-1]+a; ^ user.cpp:50:18: warning: array subscript has type ‘char’ [-Wchar-subscripts] s2[v2][j]=(s2[v2][j-1]+a*j)%mod; ^ user.cpp:50:29: warning: array subscript has type ‘char’ [-Wchar-subscripts] s2[v2][j]=(s2[v2][j-1]+a*j)%mod; ^ user.cpp:15:27: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nr.in","r",stdin); ^ user.cpp:16:29: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nr.out","w",stdout); ^ user.cpp:18:15: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:19:15: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&b); ^