c++ map嵌套队列(队列嵌套结构体指针)ok


map中嵌套队列,队列中是结构体,有一个问题,结构体中的值不更新

#include 

#include 

#include

//#include

 

using namespace std;

 

struct RevData{

int size;

char data[1000];

} recv_data;

 

map<string, queue<RevData>> amap;

 

HANDLE hMutex;

 

DWORD WINAPI Fun1(LPVOID)//创建多线程函数,函数返回值为DWORD WINAPI,一定要是这个,否则会出错

 

{

int index = 0;

while (true) {

char* aaa = "abcde";

WaitForSingleObject(hMutex, INFINITE);//获取等待资源,一直等待,知道获取"screen"资源后,才返回

queue<RevData> queue1 = amap[aaa];

 

RevData recvd;

recvd.size = index;

char* chard = "abcde";

memset(recvd.data, '\0', 1000);

memcpy(recvd.data, chard, 5);

//recvd.data = chard;

queue1.push(recvd);

amap[aaa] = queue1;

ReleaseMutex(hMutex);//释放资源独占函数

index++;

//Sleep(20);

}

}

DWORD WINAPI Fun2(LPVOID)//创建多线程函数,函数返回值为DWORD WINAPI,一定要是这个,否则会出错

{

while (true){

char* aaa = "abcde";

 

map<string, queue<RevData>>::iterator iter;

WaitForSingleObject(hMutex, INFINITE);//获取等待资源,一直等待,知道获取"screen"资源后,才返回

iter = amap.find(aaa);

if (iter != amap.end()) {

queue<RevData> queue1 = amap[aaa];

if (!queue1.empty()) {

RevData recv = queue1.front();

cout << recv.data << endl;

cout << recv.size << endl;

queue1.pop();

ReleaseMutex(hMutex);//释放资源独占函数

//Sleep(20);

} 

}

else {

cout << "支线程1" << endl;

}

}

}

调用代码:

AllocConsole();

freopen("CONOUT$", "w", stdout);

hMutex = CreateMutex(NULL, FALSE, _T("screen"));

queue<RevData> queue1;

char* aaa = "abcde";

amap[aaa] = queue1;

HANDLE handle1 = CreateThread(NULL, 0, Fun1, NULL, 0, NULL);//创建多线程

 

//hMutex = CreateMutex(NULL, FALSE, "screen");//创建资源独占函数CreateMutex,该函数的功能是独占一个资源或者线程

 

CloseHandle(handle1);//释放线程

HANDLE handle2 = CreateThread(NULL, 0, Fun2, NULL, 0, NULL);//创建多线程

 

   //hMutex = CreateMutex(NULL, FALSE, "screen");//创建资源独占函数CreateMutex,该函数的功能是独占一个资源或者线程

 

CloseHandle(handle2);//释放线程


问题原因:队列中是对象,等于号时,是复制对象,不是地址传递,queue<RevData> queue1 = amap[aaa];

这句代码中,queue1并不是map中的队列,而是map中队列的拷贝,所以pop也不是map中队列的pop,

如果不用指针,解决方法是再设置一下,代码如下:

DWORD WINAPI Fun2(LPVOID)//创建多线程函数,函数返回值为DWORD WINAPI,一定要是这个,否则会出错

{

while (true){

Sleep(20);

char* aaa = "abcde";

map<string, queue<RevData>>::iterator iter;

WaitForSingleObject(hMutex, INFINITE);//获取等待资源,一直等待,知道获取"screen"资源后,才返回

iter = amap.find(aaa);

if (iter != amap.end()) {

//queue queue1 = amap[aaa];

if (!amap[aaa].empty()) {

RevData recv = amap[aaa].front();

cout << recv.data << endl;

cout << recv.size << endl;

int lenga = amap[aaa].size();

amap[aaa].pop();

int lenga2 = amap[aaa].size();

ReleaseMutex(hMutex);//释放资源独占函数

 

}

}

else {

cout << "支线程1" << endl;

}

 

}

 

}




队列里面是指针:

#include 

#include 

#include

//#include

 

using namespace std;

 

struct RevData{

int size;

char data[1000];

} recv_data;

 

map<string, queue<RevData*>> amap;

 

HANDLE hMutex;

 

DWORD WINAPI Fun1(LPVOID)//创建多线程函数,函数返回值为DWORD WINAPI,一定要是这个,否则会出错

 

{

int index = 0;

while (true) {

char* aaa = "abcde";

WaitForSingleObject(hMutex, INFINITE);//获取等待资源,一直等待,知道获取"screen"资源后,才返回

queue<RevData*> queue1 = amap[aaa];

 

RevData recvd;

recvd.size = index;

char* chard = "abcde";

memset(recvd.data, '\0', 1000);

memcpy(recvd.data, chard, 5);

//recvd.data = chard;

queue1.push(&recvd);

amap[aaa] = queue1;

ReleaseMutex(hMutex);//释放资源独占函数

index++;

//Sleep(20);

}

 

}

DWORD WINAPI Fun2(LPVOID)//创建多线程函数,函数返回值为DWORD WINAPI,一定要是这个,否则会出错

 

{

 

while (true)

 

{

char* aaa = "abcde";

 

map<string, queue<RevData*>>::iterator iter;

WaitForSingleObject(hMutex, INFINITE);//获取等待资源,一直等待,知道获取"screen"资源后,才返回

iter = amap.find(aaa);

if (iter != amap.end()) {

 

 

queue<RevData*> queue1 = amap[aaa];

if (!queue1.empty()) {

RevData* recv = queue1.front();

cout << recv->data << endl;

cout << recv->size << endl;

queue1.pop();

ReleaseMutex(hMutex);//释放资源独占函数

//Sleep(20);

 

}

 

}

else {

cout << "支线程1" << endl;

}

 

}

 

}

 

AllocConsole();

freopen("CONOUT$", "w", stdout);

hMutex = CreateMutex(NULL, FALSE, _T("screen"));

queue<RevData*> queue1;

char* aaa = "abcde";

amap[aaa] = queue1;

HANDLE handle1 = CreateThread(NULL, 0, Fun1, NULL, 0, NULL);//创建多线程

 

//hMutex = CreateMutex(NULL, FALSE, "screen");//创建资源独占函数CreateMutex,该函数的功能是独占一个资源或者线程

 

CloseHandle(handle1);//释放线程

HANDLE handle2 = CreateThread(NULL, 0, Fun2, NULL, 0, NULL);//创建多线程

 

  //hMutex = CreateMutex(NULL, FALSE, "screen");//创建资源独占函数CreateMutex,该函数的功能是独占一个资源或者线程

 

CloseHandle(handle2);//释放线程

 

下面是失败的,map中放队列指针,队列指针中放结构体指针

#include 

#include 

#include

#include 

#include 

//#include

 

using namespace std;

 

struct RevData{

int size;

char data[1000];

} recv_data;

 

map<string, queue<RevData*>*> amap;

 

HANDLE hMutex;

 

 

DWORD WINAPI Fun1(LPVOID)//创建多线程函数,函数返回值为DWORD WINAPI,一定要是这个,否则会出错

 

{

int index = 0;

while (true) {

char* aaa = "abcde";

WaitForSingleObject(hMutex, INFINITE);//获取等待资源,一直等待,知道获取"screen"资源后,才返回

queue<RevData*>* queue1 = amap[aaa];

 

RevData recvd;

RevData *recvp;

char* chard = "abcde";

//memset(&recvd, '\0', sizeof(struct RevData));

strcpy(recvd.data, chard);

recvd.size = index;

//recvd.data = chard;

recvp = (RevData*)malloc(sizeof(RevData));

memcpy(recvp, &recvd, sizeof(RevData));

queue1->push(recvp);

index++;

Sleep(50);

//amap[aaa] = queue1;

ReleaseMutex(hMutex);//释放资源独占函数

 

}

 

}

DWORD WINAPI Fun2(LPVOID)//创建多线程函数,函数返回值为DWORD WINAPI,一定要是这个,否则会出错

{ 

while (true){

char* aaa = "abcde";

WaitForSingleObject(hMutex, INFINITE);//获取等待资源,一直等待,知道获取"screen"资源后,才返回

map<string, queue<RevData*>*>::iterator iter;

iter = amap.find(aaa);

if (iter != amap.end()) {

queue<RevData*>* queue1 = amap[aaa];

if (!queue1->empty()) {

RevData* recv = queue1->front();

cout << (*recv).data << endl;

cout << recv->size << endl;

int lenga = queue1->size();

queue1->pop();

int lenga2 = queue1->size();

}

}

else {

cout << "支线程1" << endl;

}

Sleep(50);

ReleaseMutex(hMutex);//释放资源独占函数

}

}

 

调用代码:

hMutex = CreateMutex(NULL, FALSE, _T("screen"));

queue<RevData*> queue1;

queue<RevData*>* queue2;

for (int i = 0; i < 10; i++) {

RevData recvD;

recvD.size = i;

strcpy(recvD.data, "hello");

RevData* recvp = (RevData*)malloc(sizeof(RevData));

memcpy(recvp, &recvD, sizeof(RevData));

queue1.push(recvp);// recvp);

   //queue1.push(&recvD);

}

 

//queue queue1;

char* aaa = "abcde";

queue2 = (queue<RevData*>*)malloc(sizeof(queue<RevData*>));

memcpy(queue2, &queue1, sizeof(queue<RevData*>));

amap[aaa] = queue2;

HANDLE handle1 = CreateThread(NULL, 0, Fun1, NULL, 0, NULL);//创建多线程

 

//hMutex = CreateMutex(NULL, FALSE, "screen");//创建资源独占函数CreateMutex,该函数的功能是独占一个资源或者线程

CloseHandle(handle1);//释放线程

HANDLE handle2 = CreateThread(NULL, 0, Fun2, NULL, 0, NULL);//创建多线程

   //hMutex = CreateMutex(NULL, FALSE, "screen");//创建资源独占函数CreateMutex,该函数的功能是独占一个资源或者线程

CloseHandle(handle2);//释放线程

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