c - C语言迭代中的while循环

Question

我不知道我的错误在哪里，请帮帮我。当我在用户名和密码中输入错误的数据时，它会询问"is"或“否”以重试。如果我输入 Y 作为"is"，我将无法再输入用户名。

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

int main() {  
    printf ("\n\t\t  Welcome To Your Payroll Account!");
    printf ("\n\t\t  Please Enter Your Username & Password To Proceed.");
    printf ("\n\t ********************************************************* \n \n \n");

    char password [10], username [10], ch;
    char name [10] = "username";
    char pass[10] = "password";

    char month, ename, address;
    float regpay,regov,RD,RDOT,meal;
    float SSS,PH,PI,Union,other,SSSsal,Loan,Hloan,ULoan,ELoan,TD;
    float TE,Netpay;
    int n,day,year,i;
    char input;
    char again = 'Y';

    while (again == 'Y' || again =='y') {
        printf("Username: ");
        gets (username);

        printf("Password: ");    

        for (i = 0; i<8; i++){
            ch = getch();
            password[i] = ch;
            printf ("*");
        }

        password[i] = 0;
        printf("\n Your password is: ");

        for (i =0; i<8; i++) {
            printf("%c", password[i]);    
        } 

        if(strcmp(pass,password) == 0 && strcmp(name,username) == 0) {
            printf("\n \n You are logged in! \n");
            printf("Enter # to proceed \n");
            scanf("%c", &input);    
        } else {
            printf("\n \n Incorrect username or password");
            printf("\n\n Do you want to try again? YES(Y) / NO(N) \n");
            printf("Continue? ");
            scanf("%c", &again);
            again;

        if (again == 'N' || again == 'n') {
            system ("pause");
            return 0;
        } else {
            again;      
        } 
   }  
}

system ("pause");
return 0;
}

Answer 1

    printf("Continue? ");
    scanf("%c", &again);
    again;

if (again == 'N' || again == 'n') {
    system ("pause");
    return 0;
} else {
    again;      
}

在这里，在获取字符输入时，您正在使用 scanf()

so将给出字符输入加回车。再次将获取输入字符，但输入将保留在缓冲区中。

当while循环迭代时，等待用户名输入的gets会自动从缓冲区中获取输入字符，因此用户名输入将被跳过。

解决办法是在后面添加getch()

scanf("%c", &again);

希望这对您有帮助。