向上取整、向下取整

        //向下取整
        float downF1 = 1.2;
        float downF2 = 1.6;
        
        int downI1, downI2;
        downI1 = floorf(downF1);
        downI2 = floorf(downF2);
        
        //向上取整
        float upF1 = 2.2;
        float upF2 = 2.6;
        
        int upI1, upI2;
        
        upI1 = ceil(upF1);
        upI2 = ceil(upF2);
        
        NSLog(@"---down:%d -- %d ***** up:%d -- %d", downI1, downI2, upI1, upI2);

output:

---down:1 -- 1 ***** up:3 -- 3