HJ55 挑选某个数字中所有跟7有关的数的个数

#include<iostream> 

using namespace std;

int selectNum7(int num){
	int n = 0;
	int sum = 0;
	if(num < 7){
		return sum;
	}
	else{
		for(int i = 7; i <= num;i++ ){
			if(!(i%7)||i%10==7||(i%100)/10==7||(i%1000)/100==7||(i%10000)/1000==7){
				sum += 1;
			}
	    }
		return sum;	
	}
}

int main()
{
    int value=0;
    while(cin>>value){
    	cout<<selectNum7(value)<<endl;
	}
	return 0;
}