Huawei Training Topic: beginner-(practice) Pick 7

Junior 3162 People submit 1468 people rightScore: 100 points00 hours, 00 minutes, 05 seconds

Describe	Output 7 The number of numbers, including a multiple of 7, and a number containing 7 (such as 17,27,37 ... 70,71,72,73 ... ) Number of
Knowledge points	Cycle
Run time limit	0M
Memory limit	0
Input	A positive integer n. (n not greater than 30000)
Output	The number of digits not greater than n with 7, for example, input 20, and 7 for the number including 7,14,17.
Sample input	20
Sample output	3

This question uses the method comparison general, is the cyclic traversal, may have the simple method, temporarily did not think

Here is the AC code:

1#include <iostream>2 using namespacestd;3 4 BOOLHaveseven (intnum)5 {6     intK;7      while(1)8     {9k=num%Ten;Ten         if(k==7) One             return true; ANum/=Ten; -         if(num==0) -             return false; the     } - } -  - intMain () + { -     intN; +Cin>>N; A     intI=7; at     intRe=0; -      while(i<=N) -     { -         if(i%7==0) -re++; -         Else in             if(Haveseven (i)) -re++; toi++; +     } -cout<<re<<Endl; the  *System"Pause"); $}

Huawei Training Topic: beginner-(practice) Pick 7