刷题总结（杂）

【C语言取整函数的总结】

在头文件<math.h>下，四舍五入、向上取整、向下取整。详见文档。

四舍五入： double round(double arg);//返回与arg最接近的整数 

向上取整： double ceil(double arg);//返回不小于arg的最小整数 

向下取整： double floor(double arg);//返回不大于arg的最大整数 

示例：

#include <stdio.h>
#include <math.h>//round(),floor(),ceil()
int main()
{
    //四舍五入
    printf("round(+2.33) = %+.1f ",round(2.33));
    printf("round(+2.49) = %+.1f ",round(2.49));
    printf("round(+2.5) = %+.1f ",round(2.5));
    printf("round(+2.67) = %+.1f\n",round(2.67));
    printf("round(-2.33) = %+.1f ",round(-2.33));
    printf("round(-2.49) = %+.1f ",round(-2.49));
    printf("round(-2.5) = %+.1f ",round(-2.5));
    printf("round(-2.67) = %+.1f\n",round(-2.67));
    //向下取整
    printf("floor(+2.7) = %+.1f ", floor(2.7));
    printf("floor(-2.7) = %+.1f ", floor(-2.7));
    printf("floor(-0.0) = %+.1f\n", floor(-0.0));
    //向上取整
    printf("ceil(+2.4) = %+.1f ", ceil(2.4));
    printf("ceil(-2.4) = %+.1f ", ceil(-2.4));
    printf("ceil(-0.0) = %+.1f\n", ceil(-0.0));
    return 0;
}

输出：

round(+2.33) = +2.0 round(+2.49) = +2.0 round(+2.5) = +3.0 round(+2.67) = +3.0
round(-2.33) = -2.0 round(-2.49) = -2.0 round(-2.5) = -3.0 round(-2.67) = -3.0
floor(+2.7) = +2.0 floor(-2.7) = -3.0 floor(-0.0) = -0.0
ceil(+2.4) = +3.0 ceil(-2.4) = -2.0 ceil(-0.0) = -0.0