问使用getchar()函数

EN

printf("enter srting\n");

while ((tmp=getchar()) !='\n') { \\here is my problem

    count_letters++;
        /* COUNTING WORD THAT START WITH LETTES L,A,C,H */

    while (count_letters%3==0) {
        switch (tmp) {
            case 'A': count_a++;
                break;
            case 'C': count_c++;
                break;
            case 'H': count_h++;
                break;
            case 'L': count_l++;
            default:
                break;
        }
    } /* end of count letters while  */

    n1=n2;
    n2=n3;
    n3=tmp;

    if (n1=='H' && n2=='Y' && n3=='A') {
        count_hya++;
    }



    } /* end of getchar while */
printf("\n");

printf("%d", count_letters);