View Compilation Error

0_0_32867956_1567.cpp:1:9: error: expected unqualified-id before 'if'
         if(n==0)//如果是0个数，当然要输出1.
         ^
0_0_32867956_1567.cpp:9:9: error: '__int64' does not name a type
         __int64 sum=1;
         ^
0_0_32867956_1567.cpp:11:9: error: expected unqualified-id before 'for'
         for(int i=0;i<n;i++)
         ^
0_0_32867956_1567.cpp:11:21: error: 'i' does not name a type
         for(int i=0;i<n;i++)
                     ^
0_0_32867956_1567.cpp:11:25: error: 'i' does not name a type
         for(int i=0;i<n;i++)
                         ^
0_0_32867956_1567.cpp:23:13: error: expected constructor, destructor, or type conversion before '(' token
         sort(a,a+n);//我们对负数进行排序处理，如果是偶数个数，一会直接乘上就行，否则我们要抛弃绝对值最小的那个。//https://blog.csdn.net/mengxiang000000/article/details/50570459
             ^