View Compilation Error

0_0_31549622_10696.cpp: In function 'int main()':
0_0_31549622_10696.cpp:12:10: error: expected ';' before 'int'
          int len=strlen(a);
          ^
0_0_31549622_10696.cpp:13:24: error: 'len' was not declared in this scope
          for(int j=0;j<len;j=j+2)
                        ^