Compilare: user.cpp: In function ‘void back(int)’: user.cpp:37:52: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if(st[0]+v[k]*i*i*i+50*50*50*vc[k+1]>=0&&st[0]+v[k]*i*i*i+(-50)*(-50)*(-50)*vc[k+1]<=0||st[0]+v[k]*i*i*i+50*50*50*vc[k+1]<=0&&st[0]+v[k]*i*i*i+(-50)*(-50)*(-50)*vc[k+1]>=0) ^ user.cpp: In function ‘int main()’: user.cpp:52:28: 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:53:30: 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:54:50: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d%d",&v[1],&v[2],&v[3],&v[4],&v[5]); ^