switch(a)

{

  case 0: y=2; break;

  case 1: y=7; break;

  default: y=-1;

switch(a)

{

  case 0: y=2; break;

  case 0: y=7; break;

  default: y=-1;

}

switch(a)

{

  case 0 y=2; break;

  case 1 y=7; break

  default y=-1;

}

switch(a)

{

  case 0: y=2;

  case 1: y=7;

  default: y=-1;

}