View Compilation Error

0_0_25174722_27606.cpp: In function 'int main()':
0_0_25174722_27606.cpp:7:5: error: 'an' was not declared in this scope
     an[1] = 0.5;
     ^
0_0_25174722_27606.cpp:12:24: error: 'n' was not declared in this scope
     while(~scanf("%d",&n))
                        ^