Compilare: user.cpp: In function ‘int main()’: user.cpp:2:100: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] using namespace std;int rest,nr2,nr1,i,n;int pas,step,ksol;int main(){freopen("bile6.in","r",stdin);freopen("bile6.out","w",stdout);scanf("%d",&n);nr1=n/2;nr2=(n+1)/2+n;rest=n%2;for(i=1;i<=n;i++){if(rest==0){printf("%d %d\n",nr1,nr1+i);rest=1;nr1--;}else{printf("%d %d\n",nr2,nr2+i);nr2--;rest=0;}}if(n%2==0)printf("%d\n",(n+2)/2+n);else printf("%d\n",(n+1)/2);return 0;} ^ user.cpp:2:132: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] using namespace std;int rest,nr2,nr1,i,n;int pas,step,ksol;int main(){freopen("bile6.in","r",stdin);freopen("bile6.out","w",stdout);scanf("%d",&n);nr1=n/2;nr2=(n+1)/2+n;rest=n%2;for(i=1;i<=n;i++){if(rest==0){printf("%d %d\n",nr1,nr1+i);rest=1;nr1--;}else{printf("%d %d\n",nr2,nr2+i);nr2--;rest=0;}}if(n%2==0)printf("%d\n",(n+2)/2+n);else printf("%d\n",(n+1)/2);return 0;} ^ user.cpp:2:147: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] using namespace std;int rest,nr2,nr1,i,n;int pas,step,ksol;int main(){freopen("bile6.in","r",stdin);freopen("bile6.out","w",stdout);scanf("%d",&n);nr1=n/2;nr2=(n+1)/2+n;rest=n%2;for(i=1;i<=n;i++){if(rest==0){printf("%d %d\n",nr1,nr1+i);rest=1;nr1--;}else{printf("%d %d\n",nr2,nr2+i);nr2--;rest=0;}}if(n%2==0)printf("%d\n",(n+2)/2+n);else printf("%d\n",(n+1)/2);return 0;} ^