不经典做法……

#include<iostream>
using namespace std;
int main(){
	char a,b,c,d,e,f,g,h;
	int n=0;
	cin>>a>>b>>c>>d>>e>>f>>g>>h;
	if(a=='1')	n++;
	if(b=='1')	n++;
	if(c=='1')	n++;
	if(d=='1')	n++;
	if(e=='1')	n++;
	if(f=='1')	n++;
	if(g=='1')	n++;
	if(h=='1')	n++;
	cout<<n;
	return 0;
}