1、第 4 章数 学 之 趣数学游戏的乐趣代码清单 4-1struct pointdouble x, y;double Area(point A, point B, point C)/ 边长double a, b, c = 0; / 计算出三角形 边长，分别为 a、b、cComputer(A, B, C, a, b, c)Double p = (a + b + c) / 2;return sqrt(p - a) * (p - b) * (p - c) * p); / 海伦公式/ 如果 D在三角形内，返回 true，否则返回 falsebool isInTriangle(point A, point
2、 B, point C, point D)/ Area(A, B, C)函数返回以 A、B、C为顶点的三角形的面积if(Area(A, B, D) + Area(B, C, D) + Area(C, A, D) Area(A, B, C)return false;return true; 代码清单 4-2struct pointdouble x, y;第 4 章 数字之趣 数字游戏的乐趣编程之美 微软技术面试心得264;double Product(point A, point B, point C)return (B.x - A.x) * (C.y - A.y) - (C.x - A.x)
3、* (B.y - A.y);/ A，B，C 在逆时针 方向/ 如果 D在 ABC之外，返回 false，否则返回 true/ 注：此处依赖于 A、B、C的位置关系，其位置不能调换bool isInTriangle(point A, point B, point C, point D)if (Product(A, B, D) = 0 return false;代码清单 4-3void CalcTime(double Length, / length of the stickdouble *XPos, / position of an ant, (Length / 2) currentMax =
4、XPosi / speed; else currentMax = (Length Xposi) / speed; currentMin = TotalTime - Max;if(Max currentMin)Min = currentMin; 代码清单 4-4#include int main()bool flag;bool IsUsed10;int number, revert_number, t, v;for(number = 0; number 100000; number+)flag = true;memset(IsUsed, 0, sizeof(IsUsed);t = number; revert_number = 0;for(int i = 0; i 5; i+) v = t % 10;revert_number = revert_number * 10 + v; t /= 10;if(IsUsedv) flag = false; else IsUsedv = 1; if(flag if(v 10 return 0;
