以下程序的输出结果是________。#include"stdio.h"f(intb[],intm,intn){inti,s=0;for(i=m;i<=n;i=i+2)s=s+b;returns;}main（）{intx,a[]={1,2,3,4,5,6,7,8,9};x=f(a,3,7);printf("%d",x);}