Compilare: user.cpp: In function ‘int main()’: user.cpp:16:9: warning: variable ‘difc’ set but not used [-Wunused-but-set-variable] int difc; ^ user.cpp:17:9: warning: variable ‘difa’ set but not used [-Wunused-but-set-variable] int difa; ^ user.cpp:19:34: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf( fin, "%d%d", &m, &n ); ^ user.cpp:22:41: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf( fin, "%d", &a[i][j]); ^