在程序中先声明int,float,char，double型的变量，再声明 int,float,char,double类型的指针变量，并用相应存储空间初始化指针变量，分别显示这些指针变量占了多少字节，指针变量所指的变量占了多少字节。用sizeof运算符

以下是程序示例：

#include <iostream>
using namespace std;

int main() {
    int i = 10;
    float f = 3.14;
    char c = 'a';
    double d = 3.1415926;

    int *ip = &i;
    float *fp = &f;
    char *cp = &c;
    double *dp = &d;

    cout << "Size of int pointer: " << sizeof(ip) << " bytes" << endl;
    cout << "Size of float pointer: " << sizeof(fp) << " bytes" << endl;
    cout << "Size of char pointer: " << sizeof(cp) << " bytes" << endl;
    cout << "Size of double pointer: " << sizeof(dp) << " bytes" << endl;

    cout << "Size of int variable: " << sizeof(i) << " bytes" << endl;
    cout << "Size of float variable: " << sizeof(f) << " bytes" << endl;
    cout << "Size of char variable: " << sizeof(c) << " bytes" << endl;
    cout << "Size of double variable: " << sizeof(d) << " bytes" << endl;

    return 0;
}

输出：

Size of int pointer: 8 bytes
Size of float pointer: 8 bytes
Size of char pointer: 8 bytes
Size of double pointer: 8 bytes
Size of int variable: 4 bytes
Size of float variable: 4 bytes
Size of char variable: 1 bytes
Size of double variable: 8 bytes

可以看到，指针变量占用8字节，而变量i和f占用4字节，变量c占用1字节，变量d占用8字节。