```cpp
#include<bits/stdc++.h>
using namespace std;
int has_2(int n)
{
int a=0;
while(n)
{
if(n%10==2) a++;
n/=10;
}
return a;
}
int main()
{
int a,b,c=0,i;
cin>>a>>b;
for(i=a;i<=b;i++)
c+=has_2(i);
cout<<c;
}
```
by awask @ 2017-10-11 16:25:07
#include<iostream>
using namespace std;
int main()
{
int i,L,R,t,w,num=0;
cin>>L>>R;
for(i=L;i<=R;i++)
{
w=i;
while(w!=0)
{
t=w%10;
if(t==2)
num++;
w/=10;
}
}
cout<<num<<endl;
return 0;
}
by mengyuan @ 2018-02-19 16:39:17
While语句轻松搞定
by X_WT @ 2018-08-26 11:13:44
good
by peppaking8 @ 2018-11-14 20:02:33
@[mengyuan](/space/show?uid=65272) 希望更丰富的展现？使用Markdown
by peppaking8 @ 2018-11-14 20:02:52