Modify value in ng-repeat

I want to change quantity value in cart. I have insert cart intems in WebSql and cart show in Cart.html Now I want to add quantity of one item by ng-click'addQuantity()' but I don't know how.

Cart.html

<div class="item cart_box" ng-repeat="ct in cartItemList track by ct.id">
                    <div class="cart_name">
                        <p>{{ct.ItemName}}</p>
                        <span class="badge badge-balanced">{{ct.quantity}}</span>
                        <span class="cart_price" >Rs. {{ct.price}}</span>
                        <span class="cart_price">{{ct.variant}}</span>
                    </div>

                    <ul class="cart_icon">
                        <li><i class="ion-ios7-information-outline"></i></li>
                        <li><i ng-click="deleteCart()" class="ion-ios7-close-outline" style="color:red"></i></li>
                        <li><i class="ion-ios7-minus-outline"></i></li>
                        <li><i ng-click="addQuantity()" class="ion-ios7-plus-outline"></i></li>
                    </ul>
</div>

CartController.js

databaseHelper.selectCartItem().done(function(result){
        $scope.cartItemList = result;
        console.log(result);
    });

$scope.deleteCart = function(cart){
    var index = $scope.cartItemList.indexOf(cart);
    $scope.cartItemList.splice(index, 1);
    databaseHelper.deleteCart(cart.itemId);

};

$scope.addQuantity = function(){
    //What to do?
    //$scope.qunatity = ?
}

Please Help

change your html to

<li><i ng-click="addQuantity(ct)" class="ion-ios7-plus-outline"></i></li>

now inside your javascript

$scope.addQuantity = function(ct){
    ct.quantity++;
}

you can use the same approach that is applied for removing entry.

Pass on the index, grab the target object using the index and set the value.

In your HTML :

 <li><i ng-click="addQuantity($index)" class="ion-ios7-plus-outline"></i></li>

In your JS :

$scope.addQuantity = function(index ){
    $scope.cartItemList[index].quantity = 100; // Or whatever you want to put up.

}

Read more about $index here