View Compilation Error

0_0_37428299_28208.cpp: In function 'int main()':
0_0_37428299_28208.cpp:5:2: error: 'undefined' was not declared in this scope
 {undefined
  ^
0_0_37428299_28208.cpp:9:19: error: 'n' was not declared in this scope
 while(scanf("%d",&n)!=EOF)
                   ^
0_0_37428299_28208.cpp:11:2: error: 'sum' was not declared in this scope
 {sum=1;
  ^
0_0_37428299_28208.cpp:15:5: error: 'i' was not declared in this scope
 for(i=1;i<n;i++)
     ^
0_0_37428299_28208.cpp:19:1: error: expected ';' before 'sum'
 sum=(sum+1)*2;
 ^