Compilare: user.cpp: In function ‘int main()’: user.cpp:39:9: warning: unused variable ‘r’ [-Wunused-variable] int r,a=0,sol=0; ^ user.cpp:39:11: warning: unused variable ‘a’ [-Wunused-variable] int r,a=0,sol=0; ^ user.cpp:37:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("eqs.in","r",stdin); ^ user.cpp:38:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("eqs.out","w",stdout); ^ user.cpp:41:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&v2[i]); ^