Compilare: user.cpp: In function ‘int main()’: user.cpp:40:12: warning: unused variable ‘v’ [-Wunused-variable] int i, v, op, a, b; ^ user.cpp:40:15: warning: unused variable ‘op’ [-Wunused-variable] int i, v, op, a, b; ^ user.cpp:40:19: warning: unused variable ‘a’ [-Wunused-variable] int i, v, op, a, b; ^ user.cpp:40:22: warning: unused variable ‘b’ [-Wunused-variable] int i, v, op, a, b; ^ user.cpp:43:26: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d", &n); ^ user.cpp:46:30: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d", &x); ^