Main.cc: In function ‘int mian()’:
Main.cc:18:8: error: ‘k’ was not declared in this scope
if(a[k]>0) j++;
^
Main.cc:20:6: error: ‘k’ was not declared in this scope
a[k]--;
^
Main.cc:24:3: error: ‘k’ was not declared in this scope
k++;
^