View Compilation Error

0_0_39283261_19845.cpp: In function 'int main()':
0_0_39283261_19845.cpp:45:21: error: 'a' was not declared in this scope
   45 |                 num[a]=1;
      |                     ^
0_0_39283261_19845.cpp:46:21: error: 'b' was not declared in this scope
   46 |                 num[b]=1;
      |                     ^