题解 | #挑7#

#include <stdio.h>

int main() {
    int a, b = 0;
    while(scanf("%d",&a)!=EOF)
    {    
    b = 0;
    for(int i = 1;i<=a;i++)
    {
        int tem = i;
        if(i%7 == 0)
            b++;
        else
            while(tem)
            {
                if(tem%10 == 7)
                    {
                        b++;
                        break;
                    }
                tem/=10;
            }
        
    }
    printf("%d",b);
    }
}