answer.code:2:12: warning: ‘c’ initialized and declared ‘extern’
    2 | extern int c[6][18]={};
      |            ^
answer.code:3:12: warning: ‘w’ initialized and declared ‘extern’
    3 | extern int w[6]={0,3,4,7,8,9};
      |            ^
answer.code:4:12: warning: ‘v’ initialized and declared ‘extern’
    4 | extern int v[6]={0,4,5,10,11,13};
      |            ^
answer.code:5:12: warning: ‘x’ initialized and declared ‘extern’
    5 | extern int x[6]={0};
      |            ^
answer.code: In function ‘int main()’:
answer.code:58:10: error: ‘system’ was not declared in this scope
   58 |          system("pause");
      |          ^~~~~~