Q.1~10000사이에 8이 몇번 나오는가?

// while

int x = 1;
int count = 0;

while(x <= 10000) {

    int y = x;
    while(y > 0) {

        if(y % 10 == 8) {
            count++;
        }

        y /= 10;
    }
    x++;
}
System.out.println(count);

 

// for

int count = 0;
for(int x = 1 ; x <= 10000 ; x++) {

    for(int y = x ; y > 0 ; y/= 10) {
        if(y % 10 == 8) {
            count++;
        }
    }
}
System.out.println(count);