C语言数学函数ceil简介 函数名: ceil 用 法: double ceil(double x); 功 能: 返回大于或者等于指定表达式的最小整数 头文件: math.h 程序例 #include < stdio.h > #include <math.h> int main(void) { double number = 123.54; double down, up; down = floor (number); up = ceil(number); printf("original number %5.2lf\n", number); printf("number rounded down %5.2lf\n", down); printf("number rounded up %5.2lf\n", up); return 0; } 运行结果: original number 123.54 number rounded down 123.00 number rounded up 124.00