C++ 为什么std:：cout正在更改我的变量？

我以为我疯了，但是我的堆分配值在传递到

cout时被修改，当你得到这样奇怪的效果时，总是意味着某种内存损坏，因为内存管理错误

在valgrind下运行
delay\u测试
，会产生数千个错误：

==28617== Invalid write of size 8
==28617==    at 0x400EED: ring_buffer<signal<double> >::push(signal<double>) (in /tmp/sig/delay_test)
==28617==    by 0x400C10: delay::delay(double, unsigned long, signal<double>) (in /tmp/sig/delay_test)
==28617==    by 0x401065: main (in /tmp/sig/delay_test)
==28617==  Address 0x5ab40c0 is 0 bytes inside a block of size 16,384 free'd
==28617==    at 0x4C2D6FA: operator delete[](void*) (vg_replace_malloc.c:621)
==28617==    by 0x400E04: ring_buffer<signal<double> >::~ring_buffer() (in /tmp/sig/delay_test)
==28617==    by 0x400BDC: delay::delay(double, unsigned long, signal<double>) (in /tmp/sig/delay_test)
==28617==    by 0x401065: main (in /tmp/sig/delay_test)
==28617==  Block was alloc'd at
==28617==    at 0x4C2C8F9: operator new[](unsigned long) (vg_replace_malloc.c:423)
==28617==    by 0x400E3E: ring_buffer<signal<double> >::ring_buffer(unsigned long) (in /tmp/sig/delay_test)
==28617==    by 0x400BB4: delay::delay(double, unsigned long, signal<double>) (in /tmp/sig/delay_test)
==28617==    by 0x401065: main (in /tmp/sig/delay_test)
==28617== 
...
...
==28617== HEAP SUMMARY:
==28617==     in use at exit: 0 bytes in 0 blocks
==28617==   total heap usage: 5 allocs, 5 frees, 92,160 bytes allocated
==28617== 
==28617== All heap blocks were freed -- no leaks are possible
==28617== 
==28617== For counts of detected and suppressed errors, rerun with: -v
==28617== ERROR SUMMARY: 2060 errors from 8 contexts (suppressed: 0 from 0)

==28617==大小为8的无效写入
==28617==0x400EED时：环形缓冲区：：推送（信号）（in/tmp/sig/delay_测试）
==28617==by 0x400C10:delay:：delay（双精度，无符号长，信号）（in/tmp/sig/delay_测试）
==28617==0x401065:main（in/tmp/sig/delay_测试）
==28617==地址0x5ab40c0是大小为16384 free'd的块中的0字节
==28617==at 0x4C2D6FA:运算符delete[]（void*）（vg_replace_malloc.c:621）
==28617==by 0x400E04:ring\u buffer:：~ring\u buffer（）（在/tmp/sig/delay\u测试中）
==28617==by 0x400BDC:delay:：delay（双精度，无符号长，信号）（in/tmp/sig/delay_测试）
==28617==0x401065:main（in/tmp/sig/delay_测试）
==28617==块在
==28617==at 0x4C2C8F9:运算符新[]（无符号长）（vg_替换_malloc.c:423）
==28617==by 0x400E3E:ring\u buffer:：ring\u buffer（无符号长）（in/tmp/sig/delay\u测试）
==28617==by 0x400BB4:delay:：delay（双精度，无符号长，信号）（in/tmp/sig/delay_测试）
==28617==0x401065:main（in/tmp/sig/delay_测试）
==28617== 
...
...
==28617==堆摘要：
==28617==在出口处使用：0块中的0字节
==28617==总堆使用率：5个alloc，5个free，分配92160字节
==28617== 
==28617==所有堆块都已释放--不可能存在泄漏
==28617== 
==28617==对于检测到的和抑制的错误计数，请使用：-v重新运行
==28617==错误摘要：来自8个上下文的2060个错误（已抑制：来自0的0）

在释放内存后，您正在从内存进行读写操作，也就是说，正在更改的内存位置不是您的变量，它们位于已释放的内存中，然后为其他内容重新分配

您的
ring\u buffer
管理动态分配的内存，但没有用户定义的复制构造函数或赋值运算符。这意味着它完全坏了。
实际上没有任何计时，没有线程或任何东西。我在模拟信号，所以一切都以离散的时间步长运行。我知道它肯定是在
内部被修改的，但没有明显的错误
cout
不会改变传递给它的参数。也许你的
get
函数或
操作你的代码中有很多问题-new[]后面必须跟delete[]，违反规则3等等@KyleRush你知道规则3/5吗？为什么违反它会导致内存泄漏和/或UB？默认的
环缓冲区的构造函数没有初始化任何东西，它会创建一个立即被销毁的匿名对象。缺少赋值运算符会导致
buf=ring\u buffer（buffer\u size）之后出现未定义的行为。是的，就是这样。在ring_buffer中定义了必要的复制构造函数，现在它可以正常工作了。看起来我有一些关于C++对象实例化过程的阅读。谢谢
# Project Definiton

cmake_minimum_required(VERSION 3.5)
project("ring_buffer_mvce")

set_property(GLOBAL PROPERTY CXX_STANDARD 14)
set_property(GLOBAL PROPERTY CXX_STANDARD_REQUIRED ON)

# Automated Unit Test Configuration
enable_testing()

add_executable(delay_test
  src/signals/delay.cpp
  src/test/delay_test.cpp)

add_test(delay_test delay_test)

#include "delay.hpp"

delay::delay(double time, size_t buffer_size, signal<double> initial_condition) {
    this->time = time;
    buf = ring_buffer<signal<double> >(buffer_size);
    for (int i = 0; i < buffer_size; i++) {
        buf.push(initial_condition);
    }
}

delay::~delay() {
}

signal<double> delay::apply(signal<double> s) {
    // Add the current signal to the delay buffer
    buf.push(s);

    // Check to see if our current time has elapsed
    double cur_time_delta = s.get_timestamp() - buf.peek().get_timestamp();
    if (cur_time_delta >= (time - DELAY_EPSILON)) {
        buf.pop();
    }

    return buf.peek();
}

#ifndef __DELAY_H__
#define __DELAY_H__

#include <cstddef>
#include <limits>
#include "signal.hpp"
#include "filter.hpp"
#include "../utils.h"

#define DELAY_EPSILON 0.00001

class delay : public filter<double> {
    public:
    delay(double time, size_t buffer_size, signal<double> initial_condition);
    ~delay();

    virtual signal<double> apply(const signal<double>);

    private:
    double time;
    ring_buffer<signal<double> > buf;
};

#endif

#ifndef __FILTER_HPP__
#define __FILTER_HPP__

#include "signal.hpp"

template <class t>
class filter {
    public:
    virtual signal<t> apply(const signal<t>) = 0;
};

#endif

#ifndef __SIGNAL_HPP__
#define __SIGNAL_HPP__

#include <algorithm>

template <class t>
class signal {
    public:
    signal<t>(t value, double timestamp);

    signal<t>();

    t get();
    double get_timestamp();

    private:
    t value;
    double timestamp;
};


template <class t>
signal<t>::signal(t value, double timestamp) {
    this->value = value;
    this->timestamp = timestamp;
}

template <class t>
signal<t>::signal() {
    timestamp = -1;
}

template <class t>
double signal<t>::get_timestamp() {
    return timestamp;
}


template <class t>
t signal<t>::get() {
    return value;
}

#endif

#ifndef __UTILS_H__
#define __UTILS_H__

#include <cstring>

template <class t>
class ring_buffer {
    public:

    ring_buffer(size_t buffer_size);
    ring_buffer();
    ~ring_buffer();
    void push(t data);
    t peek();
    t pop();

    private:
    t* buffer;
    int data_start_idx;
    int data_end_idx;
    size_t size;
};

template <class t>
ring_buffer<t>::ring_buffer(size_t buffer_size) {
    buffer = new t[buffer_size];
    size = buffer_size;
    data_start_idx = 0;
    data_end_idx = 0;
}

template <class t>
ring_buffer<t>::ring_buffer() {
    ring_buffer(64);
}

template <class t>
ring_buffer<t>::~ring_buffer() {
    delete[] buffer;
}

template <class t>
t ring_buffer<t>::peek() {
    return buffer[data_start_idx];
}

template <class t>
t ring_buffer<t>::pop() {
    t data = buffer[data_start_idx];
    data_start_idx = (data_start_idx + 1) % size;
    return data;
}

template <class t>
void ring_buffer<t>::push(t data) {
    buffer[data_end_idx] = data;
    data_end_idx = (data_end_idx + 1) % size;
}

#endif

#include <iostream>
#include <stdio.h>
#include "../signals/signal.hpp"
#include "../signals/filter.hpp"
#include "../signals/delay.hpp"

int main(int argc, char **argv) {
    delay d = delay(0.5, 1024, signal<double>(0, 0));

    double sig = 0;
    double t = 0;
    signal<double> s = signal<double>(0, 0);
    while (true) {
        s = d.apply(signal<double>(sig, t));
        std::cout << "Signal out of delay filter: (" << s.get() << ", " << s.get_timestamp() << ").\n";

        sig += 1;
        t += 0.1;

        getchar();
    }

    return 0;
}

==28617== Invalid write of size 8
==28617==    at 0x400EED: ring_buffer<signal<double> >::push(signal<double>) (in /tmp/sig/delay_test)
==28617==    by 0x400C10: delay::delay(double, unsigned long, signal<double>) (in /tmp/sig/delay_test)
==28617==    by 0x401065: main (in /tmp/sig/delay_test)
==28617==  Address 0x5ab40c0 is 0 bytes inside a block of size 16,384 free'd
==28617==    at 0x4C2D6FA: operator delete[](void*) (vg_replace_malloc.c:621)
==28617==    by 0x400E04: ring_buffer<signal<double> >::~ring_buffer() (in /tmp/sig/delay_test)
==28617==    by 0x400BDC: delay::delay(double, unsigned long, signal<double>) (in /tmp/sig/delay_test)
==28617==    by 0x401065: main (in /tmp/sig/delay_test)
==28617==  Block was alloc'd at
==28617==    at 0x4C2C8F9: operator new[](unsigned long) (vg_replace_malloc.c:423)
==28617==    by 0x400E3E: ring_buffer<signal<double> >::ring_buffer(unsigned long) (in /tmp/sig/delay_test)
==28617==    by 0x400BB4: delay::delay(double, unsigned long, signal<double>) (in /tmp/sig/delay_test)
==28617==    by 0x401065: main (in /tmp/sig/delay_test)
==28617== 
...
...
==28617== HEAP SUMMARY:
==28617==     in use at exit: 0 bytes in 0 blocks
==28617==   total heap usage: 5 allocs, 5 frees, 92,160 bytes allocated
==28617== 
==28617== All heap blocks were freed -- no leaks are possible
==28617== 
==28617== For counts of detected and suppressed errors, rerun with: -v
==28617== ERROR SUMMARY: 2060 errors from 8 contexts (suppressed: 0 from 0)