Main.cc: In function 'int main()':
Main.cc:5:7: error: 'n' was not declared in this scope
cin>>n;
^
Main.cc:13:10: error: 'k' was not declared in this scope
a[i+1]=k;
^
Main.cc:11:7: warning: unused variable 'c' [-Wunused-variable]
int c=a[i];
^