cmd提示NOTE: If in doubt, on Unix-ish systems use './config'.

这个提示是在您执行一个命令时出现的，它意味着您可以使用 `./config` 来替代原先的命令，以确保在 Unix 系统上能够正确运行。

通常，这个提示是由于您在 Windows 系统上尝试运行一些 Unix 或 Linux 系统下的命令或脚本所导致的。在 Windows 上，命令的执行方式通常不同于 Unix 系统，因此可能会导致某些问题。

如果您正在尝试在 Windows 上运行一个 Unix/Linux 系统下的命令或脚本，建议您先确认该命令或脚本是否有 Windows 版本或兼容版本可用。如果没有，您可以考虑在虚拟机中运行 Unix/Linux 系统，或者使用 WSL (Windows Subsystem for Linux) 来运行这些命令或脚本。

如果您确定需要在 Windows 上运行这些命令或脚本，那么您可以尝试使用 `./config` 命令来代替原先的命令，或者参考相关文档进行调整。

相关问题

(Telephone Number Word Generator) Standard telephone keypads contain the digits 0 through 9. The numbers 2 through 9 each have three letters associated with them, as is indicated by the following table: Many people find it difficult to memorize phone numbers, so they use the correspondence between digits and letters to develop seven-letter words that correspond to their phone numbers. For example, a person whose telephone number is 686-2377 might use the correspondence indi- cated in the above table to develop the seven-letter word “NUMBERS.” Businesses frequently attempt to get telephone numbers that are easy for their clients to remember. If a business can advertise a simple word for its customers to dial, then no doubt the business will receive a few more calls. Each seven-letter word corresponds to exactly one seven-digit telephone number. The restaurant wishing to increase its take-home business could surely do so with the number 825-3688 (i.e., “TAKEOUT”). Each seven-digit phone number corresponds to many separate seven-letter words. Unfortunately, most of these represent unrecognizable juxtaposi- tions of letters. It’s possible, however, that the owner of a barber shop would be pleased to know that the shop’s telephone number, 424-7288, corresponds to “HAIRCUT.” A veterinarian with the phone number 738-2273 would be happy to know that the number corresponds to “PETCARE.” Write a C++ program that, given a seven-digit number, writes to a file every possible seven-letter word corresponding to that number. There are 2187 (3 to the seventh power) such words. Avoid phone numbers with the digits 0 and 1.

Sure, I can help you with that! Here's the C++ code to generate all possible seven-letter words for a given seven-digit phone number:

#include <iostream>
#include <fstream>
#include <string>
using namespace std;

// Function to generate all possible seven-letter words for a given phone number
void generateWords(string number, string word, int index, ofstream& outfile) {
    // Base case: all digits have been processed
    if (index == number.size()) {
        outfile << word << endl;  // write the word to the output file
        return;
    }

    // Generate all possible letters for the current digit
    string letters = "";
    switch (number[index]) {
        case '2':
            letters = "ABC";
            break;
        case '3':
            letters = "DEF";
            break;
        case '4':
            letters = "GHI";
            break;
        case '5':
            letters = "JKL";
            break;
        case '6':
            letters = "MNO";
            break;
        case '7':
            letters = "PQRS";
            break;
        case '8':
            letters = "TUV";
            break;
        case '9':
            letters = "WXYZ";
            break;
    }

    // Recursively generate words for the remaining digits
    for (int i = 0; i < letters.size(); i++) {
        generateWords(number, word + letters[i], index + 1, outfile);
    }
}

int main() {
    string number;
    cout << "Enter a seven-digit phone number (no 0's or 1's): ";
    cin >> number;

    // Open an output file to write the generated words
    ofstream outfile("words.txt");

    // Generate all possible seven-letter words
    generateWords(number, "", 0, outfile);

    // Close the output file
    outfile.close();

    cout << "Done! Check the output file 'words.txt' for the generated words." << endl;
    return 0;
}

To use this program, simply run it in a C++ compiler and enter a seven-digit phone number (without any 0's or 1's) when prompted. The program will generate all possible seven-letter words corresponding to that phone number and write them to a file called "words.txt".

用C++求解Some number of people (this number is even) have stood in a circle. The people stand in the circle evenly. They are numbered clockwise starting from a person with the number 11. Each person is looking through the circle's center at the opposite person.You don't know the exact number of people standing in the circle (but this number is even, no doubt). It is known that the person with the number ais looking at the person with the number b (and vice versa, of course). What is the number associated with a person being looked at by the person with the number c? If, for the specified a, b, and c, no such circle exists, output -1.

这道题可以使用数学方法来解决。首先，我们可以将每个人看作圆周上的一个点，并将他们按顺序排列。由于每个人都在看着位于他们对面的人，所以可以将他们两两配对，并将他们连成一条线段。如下图所示：

 8-------7
 |       |
 1-------6
 |       |
 2-------5
 |       |
 3-------4

其中，a和b被连成一条线段，c和d被连成一条线段，依此类推。由于人数是偶数，所以每个人都能被配对。现在的问题是，给定a和b，找到c对应的数字。

我们可以从a开始顺时针数数，每数到一个人，就去找他所对应的人。如果在数数的过程中，我们数到了b对应的人，那么我们就得到了整个环的长度。根据这个长度，我们就可以得到每个人对应的数字。

具体来说，我们可以将a的数字设为11，然后顺时针遍历每个人，直到数到b对应的人。假设此时已经数了k个人，那么整个环的长度就是k*2。接下来，我们可以从a开始继续顺时针数数，数到第k/2个人就是c对应的数字。如果k是奇数，那么c对应的数字不存在，输出-1。

下面是C++的代码实现：