c语言入门：代码不理解

Question

#include <stdio.h>
#include <ctype.h>
int main(void)
{
    char ch;
    
    printf("Give me a letter of the alphabet, and I will give ");
    printf("an animal name\nbeginning with that letter.\n");
    printf("Please type in a letter; type # to end my act.\n");
    while ((ch = getchar()) != '#')
    {
        if('\n' == ch)
            continue;
        if (islower(ch))     /* lowercase only          */
            switch (ch)
        {
            case 'a' :
                printf("argali, a wild sheep of Asia\n");
                break;
            case 'b' :
                printf("babirusa, a wild pig of Malay\n");
                break;
            case 'c' :
                printf("coati, racoonlike mammal\n");
                break;
            case 'd' :
                printf("desman, aquatic, molelike critter\n");
                break;
            case 'e' :
                printf("echidna, the spiny anteater\n");
                break;
            case 'f' :
                printf("fisher, brownish marten\n");
                break;
            default :
                printf("That's a stumper!\n");
        }                /* end of switch           */
        else
            printf("I recognize only lowercase letters.\n");
        while (getchar() != '\n')
            continue;      /* skip rest of input line */
        printf("Please type another letter or a #.\n");
    }                        /* while loop end          */
    printf("Bye!\n");
    
    return 0;
}

这个while循环刚开始的第一个if
if('\n' == ch)
continue;
这个有什么用
然后循环最后的这个while内循环
while (getchar() != '\n')
continue;
书上说是跳过输入行的剩余部分是什么意思

Answer 1

if('\n' == ch)
continue;      跳过你每次输入之前的无效换行符号

while (getchar() != '\n')
continue;          效果就是每次输入只会读取你的第一个符号无论输入多长