C語言中輸入單個(gè)字符會(huì)屏蔽回車符如何解決

scanf("%d",&n);
getchar(); //專門用來讀取上次輸入的回車符號(hào)
scanf("%c",&c);

scanf("%d",&n)
fflush(stdin); //清空輸入流緩沖區(qū)的字符，注意必須引入#include <stdlib.h>頭文件
scanf("%c",&c);

#include<stdio.h>
int main() {
 int a;
 char s1[100];
 char s2[100];
 scanf("%d", &a);
 scanf("%s", s1);
 scanf("%s", s2);
 printf("a = %d\n", a);
 printf("s1 = %s\n", s1);
 printf("s2 = %s\n", s2);
 return 0;
}

2019
hello
world

a = 2019
s1 = hello
s2 = world

#include<stdio.h>
int main() {
  int a;
  char s1;
  char s2;
  scanf("%d", &a);
  scanf("%c", &s1);
  scanf("%c", &s2);
  printf("a = %d\n", a);
  printf("s1 = %c\n", s1);
  printf("s2 = %c\n", s2);
  return 0;
}

2019
A
B

a = 2019
s1 =
s2 = A

#include<stdio.h>
int main() {
 int a;
 char s1;
 char s2;
 scanf("%d", &a);
 getchar(); // 吸收"\n"
 scanf("%c", &s1);
 getchar(); // 吸收"\n"
 scanf("%c", &s2);
 printf("a = %d\n", a);
 printf("s1 = %c\n", s1);
 printf("s2 = %c\n", s2);
 return 0;
}

#include<stdio.h>
int main() {
 int a;
 char s1;
 char s2;
 scanf("%d\n", &a); // 過濾掉回車
 scanf("%c\n", &s1);
 scanf("%c", &s2);
 printf("a = %d\n", a);
 printf("s1 = %c\n", s1);
 printf("s2 = %c\n", s2);
 return 0;
}