int main() { int i = 0; char password[20] = { 0 }; for (i = 0; i < 3; i++) { printf("请输入密码:>"); scanf("%s", password); if (strcmp(password,"123456")==0) { printf("登录成功\n"); break; } else { printf("密码错误\n"); Sleep(1000); system("cls"); } } if (i == 3) { printf("三次密码输入错误,登录失败\n"); } return 0; }