编写一个程序exp1-2.cpp，对于1∽n的每个整数n，输出log2n、√n、n、nlog2n、n2、n3、 2n和 n!的值。

编写这样一个程序需要使用C++语言，并利用一些数学函数库如cmath来进行计算。以下是一个简单的`exp1-2.cpp`程序示例：

#include <iostream>
#include <cmath> // 引入math库，用于log2, sqrt等函数

// 定义主函数
int main() {
    int n;
    std::cout << "请输入一个正整数n (1 <= n): ";
    std::cin >> n;

    // 确保输入的是正整数
    if(n <= 0) {
        std::cerr << "错误: 输入的数值必须大于0.\n";
        return 1;
    }

    // 计算并输出各个表达式的值
    double log2_n = log2(n);
    double sqrt_n = sqrt(n);
    double n_log2_n = n * log2_n;
    double n_squared = n * n;
    double n_cubed = n * n * n;
    double power_of_2 = pow(2, n);
    unsigned long long factorial = 1;
    for(int i = 1; i <= n; ++i) {
        factorial *= i;
    }

    std::cout << "log2(" << n << ") = " << log2_n << "\n";
    std::cout << "sqrt(" << n << ") = " << sqrt_n << "\n";
    std::cout << n << " * log2(" << n << ") = " << n_log2_n << "\n";
    std::cout << n << "^2 = " << n_squared << "\n";
    std::cout << n << "^3 = " << n_cubed << "\n";
    std::cout << "2^" << n << " = " << power_of_2 << "\n";
    std::cout << "n! (" << n << "!)" << " = " << factorial << "\n";

    return 0;
}

当你运行这个程序时，它会提示用户输入一个正整数n，然后依次计算并显示每个表达式的值。