Compilare: user.cpp: In function ‘int main()’: user.cpp:2:89: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] unsigned char a[211],b[211],x;int main(){int n,j,i;fscanf(fopen("nunta.in","r"),"%d",&n);a[0]=a[1]=b[0]=b[1]=1;for(i=1;i<n;++i){int t=0;for(j=1;j<=b[0]||t;++j,t/=10){x=b[j];b[j]=(t+=a[j]+b[j])%10;a[j]=x;}a[0]=b[0];b[0]=j-1;}freopen("nunta.out","w",stdout);for(i=b[0];i>0;--i)putc(b[i]+'0',stdout);return 0;} ^ user.cpp:2:256: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] unsigned char a[211],b[211],x;int main(){int n,j,i;fscanf(fopen("nunta.in","r"),"%d",&n);a[0]=a[1]=b[0]=b[1]=1;for(i=1;i<n;++i){int t=0;for(j=1;j<=b[0]||t;++j,t/=10){x=b[j];b[j]=(t+=a[j]+b[j])%10;a[j]=x;}a[0]=b[0];b[0]=j-1;}freopen("nunta.out","w",stdout);for(i=b[0];i>0;--i)putc(b[i]+'0',stdout);return 0;} ^