else if(n%2==0)
    {
        l=n/2;
        for(i=1;i<=l;i++)
        {
            sum=sum+1.0/(i*0.5);
            if(i<l)
                 printf("1/%d+",i*2);
             else printf("1/%d",i*2);
        }
        printf("=%d\n",sum);
    }
这个得怎么改。改输出答案为1/2+1/4+1/6+..的答案。。为什么输出总是错
            sum=sum+1.0/(i*0.5);
        
这个得怎么改