指针地址输出

#include<iostream>
#include<iomanip>
using namespace std;
int main()
{
char ch = 'a';
char * ptr = &ch;
char * str="即可让尽快";
cout << ptr <<'\t'<<*ptr <<endl;    //ptr输出不是地址 char * ptr默认字符串类型
cout <<(void*) ptr << '\t' << *ptr << endl;    //ptr输出不是地址 void *任意类型输出
//double num =1024.5;
//double* ptr = &num;


//cout << "ptr的值" << ptr << "\t" << &num << endl;
//cout << "ptr指向空间的值" << *ptr<<endl;

return 0;

}

加一个头文件

#include<cstdlib>

就可以用NULL

#include<iostream>#include<iomanip>#include<cstdlib>using namespace std;int main(){double * ptr=NULL ;cout << "ptr的值" << ptr <<  endl;//cout << "ptr指向空间的值" << *ptr<<endl;return 0;}