src.cpp:3:21: error: 'i' was not declared in this scope
long long int n,s,a[i],k;
^
src.cpp: In function 'int main()':
src.cpp:10:6: error: 'i' was not declared in this scope
for(i=0;i<=n;i++){
^
src.cpp:11:11: error: 'a' was not declared in this scope
cin>>a[i];
^
src.cpp:14:7: error: 'a' was not declared in this scope
sort(a+1,a+n+1);
^