View Compilation Error

0_0_15342473_16421.cpp:2:4: error: 'buf' does not name a type
    buf[id] = '\0';   //遇到这样的符号就另起一行
    ^
0_0_15342473_16421.cpp:3:4: error: expected unqualified-id before 'if'
    if(str[1] == 'b')
    ^
0_0_15342473_16421.cpp:7:4: error: expected unqualified-id before 'else'
    else
    ^