View Compilation Error

0_0_17208970_28962.cpp: In function 'int main(int, char**)':
0_0_17208970_28962.cpp:12:19: error: 'strlen' was not declared in this scope
     len=strlen(str);
                   ^
0_0_17208970_28962.cpp:13:28: error: expected ';' before ')' token
           for(i=0,i<len,i++)
                            ^
0_0_17208970_28962.cpp:19:3: error: expected primary-expression before '}' token
   }
   ^
0_0_17208970_28962.cpp:19:3: error: expected ')' before '}' token
0_0_17208970_28962.cpp:19:3: error: expected primary-expression before '}' token