foo.cc:5:1: error: expected initializer before 'unsigned'
 unsigned gcd_it(unsigned a, unsigned b) {
 ^~~~~~~~
foo.cc: In function 'int main()':
foo.cc:20:14: error: 'a' was not declared in this scope
         cin>>a[i];
              ^
foo.cc:27:28: error: 'a' was not declared in this scope
             ans+=(gcd_it(k,a[j])^i^j);
                            ^
foo.cc:27:19: error: 'gcd_it' was not declared in this scope
             ans+=(gcd_it(k,a[j])^i^j);
                   ^~~~~~
foo.cc:27:19: note: suggested alternative: 'gid_t'
             ans+=(gcd_it(k,a[j])^i^j);
                   ^~~~~~
                   gid_t

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