Question

所以我编写了以下简单程序，询问用户输入的内容，然后询问是否要再次执行此操作或退出。

Document document = null;
        Element documentElement = null;
        final DocumentBuilderFactory factory = DocumentBuilderFactory
            .newInstance();
        Element root = null;
        try {
            final DocumentBuilder builder = factory.newDocumentBuilder();
            document = builder.newDocument();

            root = document.createElement("kml");
            document.appendChild(root);
            documentElement = document.createElement("Document");
            final Element topNameElement = document.createElement("name");
            documentElement.appendChild(topNameElement);
            root.appendChild(documentElement);

            root.setAttributeNS("http://www.w3.org/2000/xmlns/","xmlns:xsi",
                "http://www.w3.org/2001/XMLSchema-instance");
            root.setAttribute("xmlns", "http://schemas.opengis.net/kml/2.2.0");
            root.setAttribute("xmlns:ar", "http://schemas.opengis.net/arml/2.0");
            root.setAttribute("xsi:schemaLocation", "http://schemas.opengis.net/kml/2.2.0  http://schemas.opengis.net/kml/2.2.0/ogckml22.xsd    http://schemas.opengis.net/arml/2.0     http://schemas.opengis.net/arml/2.0/arml.xsd");

该程序在Windows下使用mingw64编译运行正常，但是在将conio.h更改为ncurses.h并在linux下编译时，行为会发生变化。程序运行<?xml version="1.0" encoding="UTF-8"?><kml xmlns="http://schemas.opengis.net/kml/2.2.0" xmlns:ar="http://schemas.opengis.net/arml/2.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://schemas.opengis.net/kml/2.2.0 http://schemas.opengis.net/kml/2.2.0/ogckml22.xsd 	http://schemas.opengis.net/arml/2.0 	http://schemas.opengis.net/arml/2.0/arml.xsd"> <kml> </kml>函数很好但在用户点击'ENTER'后，#include <conio.h> /* or use ncurses for getch() */ #include <errno.h> #include <stdio.h> #include <string.h> #define TRUE 1 #define FALSE 0 void ReadConsoleInput(void) { char buffer[83]; char *result; printf("\nInput line of text, followed by carriage return:\n"); result = fgets(buffer, sizeof buffer, stdin); buffer[strcspn(result, "\r\n")] = '\0'; if (!result) { printf( "An error occurred reading from the console:" " error code %d\n", errno); } else { printf("\nLine length = %d\nText = %s\n", (int)strlen(result), result); } } int Repeat() { printf("Again? (Y/N): \n"); int ch; ch = getch(); return (ch == 'Y' || ch == 'y') ? TRUE : FALSE; } int main() { do { /* infinite loop */ ReadConsoleInput(); } while (Repeat()); return 0; }函数只显示，程序结束，然后用户可以输入任何字符。

linux下发生了什么不同？

（另外，如果无限循环不是我正在尝试做的正确技术，请建议。我觉得大多数程序都不依赖无限循环测试来保持开放。）

最终我计划将程序扩展为使用树数据结构存储文本并从那里学习，但我希望保持跨平台的统一性。

Answer 1

继续我的评论，完全摆脱conio.h。除了windoze / DOS之外，它是100％不可移植的。您可以使用getchar代替getch，只需考虑用户输入'\n'后剩余的输入缓冲区中剩余的Y/N。例如，您可以创建类似于以下内容的可移植实现：

#include <stdio.h>
#include <string.h>
#include <errno.h>

#define TRUE 1
#define FALSE 0

void ReadConsoleInput(void) {
    char buffer[83];
    char *result;

    printf("\nInput line of text, followed by carriage return:\n");

    result = fgets(buffer, sizeof buffer, stdin);

    if (!result) {
        printf(
            "An error occurred reading from the console:"
            " error code %d\n",
            errno);
    } else {
        buffer[strcspn(result, "\r\n")] = '\0';
        printf("\nLine length = %d\nText = %s\n", (int)strlen(result), result);
    }
}

int Repeat() {
    printf("Again? (Y/N): \n");
    int c, ch;
    ch = getchar();

    /* empty input buffer */
    for (c = getchar(); c != '\n' && c != EOF; c = getchar()) {}

    return (ch == 'Y' || ch == 'y') ? TRUE : FALSE;
}

int main (void) {
    do { /* infinite loop */
        ReadConsoleInput();
    } while (Repeat());
    return 0;
}

（在调用ch清空缓冲区之前，您需要检查EOF是否为getchar并相应处理以捕获用户取消输入）

示例使用/输出

$ ./bin/noconio

Input line of text, followed by carriage return:
a quick brown fox

Line length = 17
Text = a quick brown fox
Again? (Y/N):
y

Input line of text, followed by carriage return:
jumps over a lazy dog

Line length = 21
Text = jumps over a lazy dog
Again? (Y/N):
n

仔细看看，如果这是你的意图，请告诉我。

跨平台条件无限循环

1 个答案: