View Compilation Error

0_0_39311550_10625.cpp: In function 'ull fun_hash(std::string)':
0_0_39311550_10625.cpp:13:5: error: expected ',' or ';' before 'for'
   13 |     for(int i=1;i<=len;i++)
      |     ^~~
0_0_39311550_10625.cpp:13:17: error: 'i' was not declared in this scope
   13 |     for(int i=1;i<=len;i++)
      |                 ^