View Compilation Error

0_0_22219514_23431.cpp:20:5: error: expected initializer before 'if'
     if(flag == 0) return;                                             //flag=0,即递归出口已到
     ^
0_0_22219514_23431.cpp:21:5: error: expected unqualified-id before 'if'
     if(x == len)
     ^