笔记（循环）

int main() {
  int m = 24;
  int n = 18;
  int r;
  scanf("%d%d", &m, &n);
  while (m%n)
  {
    r = m % n;
    m = n;
    n = r;
  }

  printf("%d \n", n);

}

int main() {

  int i = 0;
  for (i = 1000; i < 2000; i++)
  {
    if ((i % 4 == 0&& i % 100 != 0)|| (i % 400 == 0))
    {
      printf("%d 是闰年 \n" , i);
    }
  }
  return 0;
}

int main() {

  int i = 0;
  int count = 0;
  for ( i = 100; i <= 200; i++)
  {
    //判断i是否为素数
    //素数规则 1. 试除法
    int j = 0;
    for ( j = 2; j < i; j++)
    {
      if (i % j == 0) {
        break;
      }
    }
    if (j == i) {
      count++;
      printf(" %d ", i);
    }
  }
  printf("\n count = %d \n",count);
  return 0;
}

int main() {
  int arr[] = { 1,2,3,4,5,6,7,8,9,10 };
  int sz = sizeof(arr) / sizeof(arr[0]);
  int max = arr[0];
  int i;
  for (i = 0; i < sz; i++)
  {
    if (arr[i] > max) {
      max = arr[i];
    }
  }
  printf("最大值为 %d", max);
  return 0;
}

int main() {
  int i = 0;
  int j = 0;
  for (i = 1; i <= 9; i++)
  {
    for (j = 1; j <= i; j++) {
      printf("%d * %d = %-2d ",i ,j , i * j);
    }
    printf("\n");
  }
  return 0;
}

void menu() {

  printf("****************************\n");
  printf("**** 1.paly  0.exit  ****\n");
  printf("****************************\n");

}
void game() {
  printf("猜数字\n");
  //1.生成一个随机数 1 - 100
  int ret = 0;
  int guess = 0; //接收猜的数字
  ret = rand() % 100 +1;
  //printf("%d \n", ret);
  //2.猜数字
  while (1)
  {
    printf("请猜数字:>");
    scanf("%d", &guess);
    if (guess > ret) {
      printf("猜大了\n");

    }
    else if(guess < ret)
    {
      printf("猜小了\n");

    }
    else {
      printf("恭喜你，猜对了\n");
      break;
    }
  }
}

int main() {

  int input = 0;
  srand((unsigned int)time(NULL));//时间戳创建随机数的起始点
  do {
    menu();
    printf("请选择>:");
    scanf("%d",&input);
    switch (input)
    {
    case 1:
      game();
      break;
    case 0:
      printf("退出游戏\n");
      break;
    default:
      printf("选择错误\n");
      break;
    }

  } while (input);
  
  
  
  return 0;
}