C语言枚举实例

/* enum.c -- uses enumerated values */
#include <stdio.h>
#include <string.h>    // for strcmp(), strchr()
#include <stdbool.h>   // C99 feature
char * s_gets(char * st, int n);

enum spectrum {red, orange, yellow, green, blue, violet};
const char * colors[] = {"red", "orange", "yellow",
    "green", "blue", "violet"};
#define LEN 30

int main(void)
{
    char choice[LEN];
    enum spectrum color;
    bool color_is_found = false;

    puts("Enter a color (empty line to quit):");
    while (s_gets(choice, LEN) != NULL && choice[0] != '\0')
    {
        for (color = red; color <= violet; color++)
        {
            if (strcmp(choice, colors[color]) == 0)
            {
                color_is_found = true;
                break;
            }
        }
        if (color_is_found)
            switch(color)
        {
            case red    : puts("Roses are red.");
                break;
            case orange : puts("Poppies are orange.");
                break;
            case yellow : puts("Sunflowers are yellow.");
                break;
            case green  : puts("Grass is green.");
                break;
            case blue   : puts("Bluebells are blue.");
                break;
            case violet : puts("Violets are violet.");
                break;
        }
        else
            printf("I don't know about the color %s.\n", choice);
        color_is_found = false;
        puts("Next color, please (empty line to quit):");
    }
    puts("Goodbye!");

    return 0;
}

char * s_gets(char * st, int n)
{
    char * ret_val;
    char * find;

    ret_val = fgets(st, n, stdin);
    if (ret_val)
    {
        find = strchr(st, '\n');   // look for newline
        if (find)                  // if the address is not NULL,
            *find = '\0';          // place a null character there
        else
            while (getchar() != '\n')
                continue;          // dispose of rest of line
    }
    return ret_val;
}