View Compilation Error

0_0_27532283_30638.cpp: In function 'int main()':
0_0_27532283_30638.cpp:8:5: error: expected initializer before 'double'
     double a[N];
     ^
0_0_27532283_30638.cpp:9:10: error: 'M' was not declared in this scope
     cin>>M;
          ^
0_0_27532283_30638.cpp:12:18: error: 'a' was not declared in this scope
             cin>>a[i];
                  ^
0_0_27532283_30638.cpp:13:14: error: 'a' was not declared in this scope
         sort(a,a+3);
              ^