system/utest/fit/examples/function_example2.cpp

// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "function_example2.h"

#include <lib/fit/function.h>

// This example demonstrates using |fit::function| to capture a member
// function (add) and applying it to each element of a vector.
namespace function_example2 {

class accumulator {
public:
    void add(int value) {
        sum += value;
    }

    int sum = 0;
};

void count_to_ten(fit::function<void(int)> fn) {
    for (int i = 1; i <= 10; i++) {
        fn(i);
    }
}

int sum_to_ten() {
    accumulator accum;
    count_to_ten(fit::bind_member(&accum, &accumulator::add));
    return accum.sum;
}

void run() {
    assert(sum_to_ten() == 55);
}

} // namespace function_example2