View Compilation Error

0_0_19163158_24762.cpp: In function 'int main()':
0_0_19163158_24762.cpp:41:18: error: 'a' was not declared in this scope
   int l = strlen(a),i,q,j,k;
                  ^
0_0_19163158_24762.cpp:44:4: error: 'i' was not declared in this scope
    i = r + 1;
    ^
0_0_19163158_24762.cpp:45:9: error: 'q' was not declared in this scope
    for (q = 2;;q++)
         ^
0_0_19163158_24762.cpp:47:5: error: 'j' was not declared in this scope
     j = i*q;
     ^
0_0_19163158_24762.cpp:48:5: error: 'k' was not declared in this scope
     k = j*q;
     ^