View Compilation Error

0_0_18984290_23179.cpp: In function 'int main()':
0_0_18984290_23179.cpp:11:15: error: 'len' was not declared in this scope
               len=strlen(str);
               ^
0_0_18984290_23179.cpp:12:19: error: 'i' was not declared in this scope
               for(i=0;i<len;i++)
                   ^