C++ 取整函数ceil和floor

有时候会遇到想要将比如1.1 1.2 1.01 1.8等类似的数据都要进位成为2的需求，怎么办呢？有函数ceil  

向上取整ceil

向下取整floor

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#include<stdio.h> #include<math.h>   intmain(void) { double number=123.45; double down,up; down=floor(number); up=ceil(number); printf("originalnumber%5.2lf\n",number); printf("numberroundeddown%5.2lf\n",down); printf("numberroundedup%5.2lf\n",up);   return0; }

运行结果：

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originalnumber123.54 numberroundeddown123.00 numberroundedup124.00