View Compilation Error

0_0_25597268_954.cpp: In function 'int main()':
0_0_25597268_954.cpp:29:8: error: 'i' was not declared in this scope
   for (i = 1; i <= n; i++)
        ^
0_0_25597268_954.cpp:35:9: error: 'j' was not declared in this scope
    for (j = 0; j<len; j++)
         ^
0_0_25597268_954.cpp:52:10: error: lvalue required as increment operand
      left++;
          ^