int main()
{
int a = 0;
int count = 0;
scanf("%d", &a);
while (a != 1)
{
if (a % 2 == 0)
{
a = a / 2;
}
else
{
a = (3 * a + 1) / 2;
}
count++;
}
printf("%d", count);
return 0;

(有相关经验，较为轻松)

//问题：一开始把判定a是偶数的条件误认为是a/2==0;