如何复制包含“"字符的数据

I'm trying to copy data that conatin ''. I'm using C++ . When the result of the research was negative, I decide to write my own fonction to copy data from one char* to another char*. But it doesn't return the wanted result ! My attempt is the following :

#include <iostream>


char* my_strcpy( char* arr_out,  char* arr_in, int bloc )
{
 char* pc= arr_out;

 for(size_t i=0;i<bloc;++i)     
 {

        *arr_out++ = *arr_in++ ;
 }

 *arr_out = '';
 return pc;
}

int main()
{
    char * out= new char[20];
    my_strcpy(out,"12345aaaaaaa  AA",20);
    std::cout<<"output data: "<< out << std::endl;
    std::cout<< "the length of my output data: " << strlen(out)<<std::endl;
    system("pause");
    return 0;
}

结果在这里:

我不明白我的代码有什么问题.