发布第三次答案

source/_posts/answer3.md

@@ -1,8 +1,10 @@
 ---
 title: 第三次作业（答案）
+date: 2020-10-30 15:53:35
 tags:
 ---
 
+
 # P108-3
 
 写出下面各逻辑表达式的值。设`a = 3`，`b = 4`，`c = 5`。
@@ -133,14 +135,11 @@ int main()
 ```C
 #include <stdio.h>
 #include <stdlib.h>
+#include <math.h>
 
 int main()
 {
     double r2 = 1;
-    double ax = 2, ay = 2,
-           bx = -2, by = 2,
-           cx = -2, cy = -2,
-           dx = 2, dy = -2;
     double x, y;
     printf("请分别输入所在位置的的x、y坐标：\nx = ");
     if (scanf("%lf", &x) != 1) {
@@ -152,12 +151,11 @@ int main()
         fprintf(stderr, "非法输入！\n");
         exit(EXIT_FAILURE);
     }
-    double da2 = (x - ax) * (x - ax) + (y - ay) * (y - ay),
-           db2 = (x - bx) * (x - bx) + (y - by) * (y - by),
-           dc2 = (x - cx) * (x - cx) + (y - cy) * (y - cy),
-           dd2 = (x - dx) * (x - dx) + (y - dy) * (y - dy);
+    x = fabs(x);
+    y = fabs(y);
+    double d2 = pow(x - 2, 2) + pow(y - 2, 2);
 
-    if (da2 <= r2 || db2 <= r2 || dc2 <= r2 || dd2 <= r2) {
+    if (d2 < r2) {
         printf("该点高度是10m\n");
     } else {
         printf("该点高度是0m\n");

source/_posts/downloads.md

@@ -44,4 +44,3 @@ tags:
 # 其它参考资料
 
 [C语言程序设计习题选编.pdf](/~zhaozuohong/resources/C-experiments.ppt)
-

source/_posts/homework.md

@@ -19,5 +19,4 @@ tags:
 # 第三次作业
 
 * [题目](/~zhaozuohong/homework3/)
-* *答案暂未开放*
-<!-- * [答案](/~zhaozuohong/answer3) -->
+* [答案](/~zhaozuohong/answer3)