C 编程 ncurses 输入验证

Question

我正在做一个使用 ncurses 并用 C 编写的小项目。我遇到了两个关于验证输入的问题。 例如，案例 1：我想验证输入是指定的特定字符，例如：a 或 b 或 c。

char choice;
printw("a. New name\n");
printw("b. Edit name\n");
printw("c. Exit\n");

scanw("%c", &choice);

if (choice == 'a')
    //Do something
else if(choice =='b') {
   //Do something
}
else if(choice == 'c') {
    exit(0);
}    

案例 2：我只想在整数范围内验证输入，例如：1 到 5。

int player_number
printw("How many players ? (1 - 5): ");
scanw("%i", &player_number);    

具有讽刺意味的是，我可以在 ncurses 上下文中找到这两个问题的解决方案。另外，当它提示用户输入时，如何使用“q”之类的按键退出我的程序。 谢谢

Answer 1

你可以试试这样的。

#include <ncurses.h>

int main()
{
    char choice = 0;
    int player_number = -1;

    initscr ( );
    do {
        mvprintw ( 1, 1,"a. New name");
        mvprintw ( 2, 1,"b. Input number");
        mvprintw ( 3, 1,"c. Exit");
        mvprintw ( 4, 1," ");
        if (( scanw("%c", &choice)) == 1) {//scanw succeeded
            if ( ! ( choice == 'a' || choice == 'b' || choice == 'c')) {
                mvprintw ( 5, 1,"invalid input, should be a, b or c");
            }
            else {
                mvprintw ( 5, 1,"                                  ");
            }
        }
    } while ( ! ( choice == 'c' || choice == 'b'));
    mvprintw ( 5, 1,"                                  ");
    if ( choice == 'b') {
        do {
            mvprintw ( 7, 1,"Enter number 0-9");
            mvprintw ( 8, 1," ");
            if (( scanw("%d", &player_number)) == 1) {//scanw succeeded
                if ( player_number < 0 || player_number > 9) {
                    mvprintw ( 9, 1,"invalid input, should be 0-9");
                }
            }
            else {//scanw failed
                mvprintw ( 9, 1,"invalid input, should be 0-9");
            }
        } while ( player_number < 0 || player_number > 9);

    }
    endwin ( );
    return 0;
}

使用 char 数组包含输入并使用getnstr() 读取输入，可以检测到q 的输入以退出程序。对于数字输入，strtol() 用于将数组转换为 int。

#include <stdio.h>
#include <stdlib.h>
#include <ncurses.h>

int main()
{
    char choice = 0;
    char instr[128] = {0};
    int player_number = -1;

    initscr ( );
    do {
        mvprintw ( 1, 1,"a. New name");
        mvprintw ( 2, 1,"b. Input number");
        mvprintw ( 3, 1,"c. Exit");
        mvprintw ( 4, 1," ");
        if (( getnstr( instr, 1)) != ERR) {//succeeded
            choice = instr[0];
            if ( ! ( choice == 'a' || choice == 'b' || choice == 'c')) {
                mvprintw ( 5, 1,"invalid input, should be a, b or c");
                if ( choice == 'q') {//quit when q is entered
                    endwin ( );
                    return 0;
                }
            }
            else {
                mvprintw ( 5, 1,"                                  ");
            }
        }
    } while ( ! ( choice == 'c' || choice == 'b'));
    mvprintw ( 5, 1,"                                  ");
    if ( choice == 'b') {
        do {
            mvprintw ( 7, 1,"Enter number 0-9");
            mvprintw ( 8, 1," ");
            if (( getnstr( instr, sizeof ( instr))) != ERR) {//succeeded
                if ( instr[0] == 'q' && instr[1] == '\0') {//quit when q is entered
                    endwin ( );
                    return 0;
                }
                player_number = strtol ( instr, NULL, 10);
                if ( player_number < 0 || player_number > 9) {
                    mvprintw ( 9, 1,"invalid input, should be 0-9");
                }
            }
            else {//failed
                mvprintw ( 9, 1,"invalid input, should be 0-9");
            }
        } while ( player_number < 0 || player_number > 9);
    }
    endwin ( );
    return 0;
}