C/C++学习笔记

回调函数

#include <stdio.h>
void fun(char* str)
{
    printf("%s
", str);
}
void callback(void (*pfun)(char*), char* s)
{
    pfun(s);
}
int main()
{
    callback(fun, "hello");
    return 0;
}

 类模板

#include <iostream>
using namespace std;
template<class T1,class T2>
class MyClass {
    private:
        T1 t1;
        T2 t2;
    public:
        MyClass(T1 a, T2 b);
        void show();
};
template<class T1, class T2>
MyClass<T1,T2>::MyClass(T1 a, T2 b):t1(a),t2(b) {}
template<class T1, class T2>
void MyClass<T1,T2>::show() {cout<<t1<<", "<<t2<<endl;}
int main() {
    MyClass<int,int> c1(3, 5);
    MyClass<double,char> c2(5.5, 'c');
    c1.show();
    c2.show();
}

 STL

stl标准模板库是c++对泛型编程思想的实现。stl广义上分为三类：algorithm算法、container容器、iterator迭代器，几乎所有的代码都采用模板类和模板函数的方式。在c++中stl被组织为13个头文件：algorithm、deque、functional、iterator、vector、list、map、memory、numeric、queue、set、statck、utility。

algorithm：

container：又称collection集合

iterator：是一种允许检查容器内元素，并实现元素遍历的数据类型

生产者消费者(linux c)

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>
pthread_mutex_t mtx = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
struct node {
    int id;
    struct node *next;
} *head = NULL;
void cleanup_handler(void* arg) {
    printf("cleanup handler.
");
    free(arg);
    (void)pthread_mutex_unlock(&mtx);
}
void* thread_func(void* arg) {
    struct node* p = NULL;
    pthread_cleanup_push(cleanup_handler, p);
    while (1) {
        pthread_mutex_lock(&mtx);
        while (head == NULL) {
            pthread_cond_wait(&cond, &mtx);
        }
        p = head;
        head = head->next;
        printf("get %d from queue
", p->id);
        free(p);
        pthread_mutex_unlock(&mtx);
    }
    pthread_cleanup_pop(0);
}
int main(int argc, char** argv) {
    pthread_t tid;
    int i;
    struct node* p;
    pthread_create(&tid, NULL, thread_func, NULL);
    for (i = 0; i < 10; i++) {
        p = malloc(sizeof(struct node));
        p->id = i;
        pthread_mutex_lock(&mtx);
        p->next = head;
        head = p;
        pthread_cond_signal(&cond);
        pthread_mutex_unlock(&mtx);
        sleep(1);
    }
    printf("xxxxxxxxxxxxxxx
");
    pthread_cancel(tid);
    pthread_join(tid, NULL);
    printf("All done
");
    return 0;
}