Main.cc: In function ‘int main()’:
Main.cc:12:9: error: redeclaration of ‘int n’
int n = 0;
^
Main.cc:8:9: note: ‘int n’ previously declared here
int n;
^
Main.cc:9:11: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
scanf ("%d",&n);
~~~~~~^~~~~~~~~