View Compilation Error

0_0_34257642_32184.cpp: In function 'int main()':
0_0_34257642_32184.cpp:5:12: error: 'o' was not declared in this scope
 {int n,sum=o,i;
            ^
0_0_34257642_32184.cpp:9:6: error: 'i' was not declared in this scope
 {for(i=1;i<=n;i++)
      ^