Compilare: user.cpp: In function ‘int main()’: user.cpp:50:29: warning: array subscript has type ‘char’ [-Wchar-subscripts] fr[mat[i][j]]++; ^ user.cpp:40:31: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d %d " ,&n,&m); ^ user.cpp:42:37: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%s " ,mat[i] + 1); ^