Angular购物车的加减

<td><button ng-click="add($index)">+</button>{{u.num}}<button ng-click="minus($index)">-</button></td>//加$scope.add = function(index){$scope.user[index].num++;}//减$scope.minus = function(index){if($scope.user[index].num>1){$scope.user[index].num--;}}