View Compilation Error

0_0_21605346_29803.cpp:1:1: error: expected unqualified-id before 'for'
 for(int i=len;i>=1;i--)//每次确定一位
 ^
0_0_21605346_29803.cpp:1:15: error: 'i' does not name a type
 for(int i=len;i>=1;i--)//每次确定一位
               ^
0_0_21605346_29803.cpp:1:20: error: 'i' does not name a type
 for(int i=len;i>=1;i--)//每次确定一位
                    ^
0_0_21605346_29803.cpp:18:5: error: expected unqualified-id before 'if'
     if(has)
     ^