From af5944bc1272c4c2276b3363dee84de636c92baa Mon Sep 17 00:00:00 2001
From: flykhan <liubo666666@outlook.com>
Date: Fri, 23 Jun 2023 17:31:07 +0800
Subject: [PATCH] day8 coding

---
 day8/d1.cpp    | 13 +++++++++++++
 day8/d10.cpp   | 41 ++++++++++++++++++++++++++++++++++++++++
 day8/d11.cpp   | 29 ++++++++++++++++++++++++++++
 day8/d12.cpp   | 32 +++++++++++++++++++++++++++++++
 day8/d12_2.cpp | 33 ++++++++++++++++++++++++++++++++
 day8/d13.cpp   | 32 +++++++++++++++++++++++++++++++
 day8/d14.cpp   | 23 +++++++++++++++++++++++
 day8/d15.cpp   | 28 +++++++++++++++++++++++++++
 day8/d16.cpp   | 22 ++++++++++++++++++++++
 day8/d17.cpp   | 22 ++++++++++++++++++++++
 day8/d2.cpp    |  0
 day8/d5.cpp    | 21 +++++++++++++++++++++
 day8/d6.cpp    | 44 +++++++++++++++++++++++++++++++++++++++++++
 day8/d7.cpp    | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++
 day8/d8.cpp    | 15 +++++++++++++++
 day8/d9.cpp    | 29 ++++++++++++++++++++++++++++
 16 files changed, 435 insertions(+)
 create mode 100644 day8/d1.cpp
 create mode 100644 day8/d10.cpp
 create mode 100644 day8/d11.cpp
 create mode 100644 day8/d12.cpp
 create mode 100644 day8/d12_2.cpp
 create mode 100644 day8/d13.cpp
 create mode 100644 day8/d14.cpp
 create mode 100644 day8/d15.cpp
 create mode 100644 day8/d16.cpp
 create mode 100644 day8/d17.cpp
 create mode 100644 day8/d2.cpp
 create mode 100644 day8/d5.cpp
 create mode 100644 day8/d6.cpp
 create mode 100644 day8/d7.cpp
 create mode 100644 day8/d8.cpp
 create mode 100644 day8/d9.cpp

diff --git a/day8/d1.cpp b/day8/d1.cpp
new file mode 100644
index 0000000..43ba3d9
--- /dev/null
+++ b/day8/d1.cpp
@@ -0,0 +1,13 @@
+#include <iostream>
+
+using namespace std;
+
+int main()
+{
+    cout << "running app" << endl;
+    int i = 0;
+    for (;;) // 死循环: 原理是 for 语句中的三个表达式都可以省略 (但是分号不能省略), 省略后的 for 语句相当于 while (1)
+        ;
+    cout << "app end" << endl;
+    return 0;
+}
\ No newline at end of file
diff --git a/day8/d10.cpp b/day8/d10.cpp
new file mode 100644
index 0000000..c45e22f
--- /dev/null
+++ b/day8/d10.cpp
@@ -0,0 +1,41 @@
+#include <iostream>
+#include <cstdlib>
+
+using namespace std;
+
+int main()
+{
+    int rows = 1;
+    cout << "请输入行数: ";
+    cin >> rows;
+    int arr[rows][3] = {}; // ?变量是否可以作为定义数组时的维度
+    int num;
+    int j = rows;
+    while (j)
+    {
+        for (int i = 0; i < 3; i++)
+        {
+            cout << "请输入值: ";
+            cin >> arr[rows - j][i];
+
+            // break 结束 for 循环
+            // 如何结束外部的 while 循环
+            if (arr[rows - j][i] == -1)
+                // break;
+                goto show;
+        }
+        j--;
+    }
+
+show:
+    for (int i = 0; i < rows; i++)
+    {
+        for (int j = 0; j < 3; j++)
+        {
+            cout << arr[i][j] << "\t";
+        }
+        cout << endl;
+    }
+
+    return 0;
+}
\ No newline at end of file
diff --git a/day8/d11.cpp b/day8/d11.cpp
new file mode 100644
index 0000000..8ad5a1b
--- /dev/null
+++ b/day8/d11.cpp
@@ -0,0 +1,29 @@
+// 求出每个人的平均成绩
+#include <iostream>
+#include <cstdlib>
+
+using namespace std;
+
+int main()
+{
+    int score[5][4] = {
+        {56, 75, 78, 89},
+        {89, 98, 76, 67},
+        {88, 88, 77, 66},
+        {67, 78, 89, 90},
+        {98, 97, 96, 95}};
+
+    float avg = 0.0f;
+    // 每个人的平均成绩
+    for (int i = 0; i < 5; i++)
+    {
+        avg = 0.0f; // 重置平均成绩, 目的: 避免上一次的平均成绩影响到这一次的平均成绩
+        for (int j = 0; j < 4; j++)
+        {
+            avg += score[i][j] / 4.0f; // 求出每个人的平均成绩
+        }
+        cout << "第" << i + 1 << "个人的平均成绩: " << avg << endl;
+    }
+
+    return 0;
+}
\ No newline at end of file
diff --git a/day8/d12.cpp b/day8/d12.cpp
new file mode 100644
index 0000000..9690cb5
--- /dev/null
+++ b/day8/d12.cpp
@@ -0,0 +1,32 @@
+// 计算某一个学科的平均成绩
+#include <iostream>
+#include <cstdlib>
+
+using namespace std;
+
+int main()
+{
+    int score[5][4] = {
+        {56, 75, 78, 89},
+        {89, 98, 76, 67},
+        {88, 88, 77, 66},
+        {67, 78, 89, 90},
+        {98, 97, 96, 95}};
+
+    string subject[] = {"语文", "数学", "化学", "物理"};
+
+    float avg = 0.0f;
+    // 每个人的平均成绩
+    for (int j = 0; j < 4; j++)
+    {
+        avg = 0.0f; // 重置平均成绩, 目的: 避免上一次的平均成绩影响到这一次的平均成绩
+        for (int i = 0; i < 5; i++)
+        {
+
+            avg += score[i][j] / 5.0f; // 求出某一个学科的平均成绩
+        }
+        cout << subject[j] << "的平均成绩: " << avg << endl;
+    }
+
+    return 0;
+}
\ No newline at end of file
diff --git a/day8/d12_2.cpp b/day8/d12_2.cpp
new file mode 100644
index 0000000..3faa2ce
--- /dev/null
+++ b/day8/d12_2.cpp
@@ -0,0 +1,33 @@
+#include <iostream>
+#include <cstdlib>
+
+using namespace std;
+
+int main(int argc, char const *argv[])
+{
+
+    int score[5][4] = {
+        {56, 75, 78, 89},
+        {89, 98, 76, 67},
+        {88, 88, 77, 66},
+        {67, 78, 89, 90},
+        {98, 97, 96, 95}};
+
+    float avg1 = 0.0f;
+    float avg2 = 0.0f;
+    float avg3 = 0.0f;
+    float avg4 = 0.0f;
+    // 计算物理学科平均
+    for (int i = 0; i < 5; i++)
+    {
+        avg1 += score[i][0] / 5.0;
+        avg2 += score[i][1] / 5.0;
+        avg3 += score[i][2] / 5.0;
+        avg4 += score[i][3] / 5.0;
+    }
+    cout << "语文的平均成绩： " << avg1 << endl;
+    cout << "数学的平均成绩： " << avg2 << endl;
+    cout << "化学的平均成绩： " << avg3 << endl;
+    cout << "物理的平均成绩： " << avg4 << endl;
+    return 0;
+}
diff --git a/day8/d13.cpp b/day8/d13.cpp
new file mode 100644
index 0000000..f3948bd
--- /dev/null
+++ b/day8/d13.cpp
@@ -0,0 +1,32 @@
+// 数组排序
+#include <iostream>
+#include <cstdlib>
+
+using namespace std;
+
+int main()
+{
+    int arr[] = {5, 2, 3, 1, 7, 6};
+    int len = sizeof(arr) / sizeof(int); // 这里的 sizeof(int) 相当于 sizeof(arr[0])
+    // 冒泡排序
+    for (int i = 0; i < len - 1; i++)
+    {
+        // i 代表轮数
+        for (int j = 0; j < len - i - 1; j++)
+        {
+            if (arr[j] > arr[j + 1])
+            {
+                // 使用异或运算交换两个数的值
+                arr[j] = arr[j] ^ arr[j + 1];
+                arr[j + 1] = arr[j] ^ arr[j + 1];
+                arr[j] = arr[j] ^ arr[j + 1];
+            }
+        }
+    }
+
+    for (int i = 0; i < len; i++)
+        cout << arr[i] << "\t";
+
+    cout << endl;
+    return 0;
+}
\ No newline at end of file
diff --git a/day8/d14.cpp b/day8/d14.cpp
new file mode 100644
index 0000000..06acc14
--- /dev/null
+++ b/day8/d14.cpp
@@ -0,0 +1,23 @@
+// 按字符串读取，读取到第一`\0`结束。
+#include <iostream>
+#include <cstdlib>
+
+using namespace std;
+
+int main()
+{
+    char arr[] = "hello";
+    cout << sizeof(arr) << endl; // 6B
+
+    // 逐个读取
+    int i = 0;
+    while (arr[i]) // arr[i] != '\0', 因为 '\0' 的 ASCII 码为 0
+    {
+        cout << arr[i++] << endl;
+    }
+    cout << endl;
+
+    // 一次读取
+    cout << arr << endl;
+    return 0;
+}
\ No newline at end of file
diff --git a/day8/d15.cpp b/day8/d15.cpp
new file mode 100644
index 0000000..cadd993
--- /dev/null
+++ b/day8/d15.cpp
@@ -0,0 +1,28 @@
+// 从键盘输入字符
+#include <iostream>
+#include <cstdlib>
+#include <cstring>
+
+using namespace std;
+
+int main()
+{
+    char name[50] = ""; // 字符数组的初始值建议给一个空字符串, 即 ""
+    cout
+        << "请输入姓名: ";
+    cin >> name;
+
+    // sizeof(字符数组)计算数组分配内存空间的大小
+    cout << "你输入的内容为" << name << ", 它的字节长度为" << sizeof(name) << endl;
+    // strlen(字符数组)输出第一个`\0`之前的字符个数
+    cout << "字符个数为" << strlen(name) << endl;
+
+    int i = 0;
+    while (name[i])
+    {
+        cout << name[i++] << "\t";
+    }
+    cout << (int)name[i] << endl; // 0 ,用于验证`\0`的 ASCII 码为 0
+
+    return 0;
+}
\ No newline at end of file
diff --git a/day8/d16.cpp b/day8/d16.cpp
new file mode 100644
index 0000000..f271c84
--- /dev/null
+++ b/day8/d16.cpp
@@ -0,0 +1,22 @@
+// 获取一个字符串 求该字符串的长度(不使用strlen)
+#include <iostream>
+
+using namespace std;
+
+int main()
+{
+    // 从键盘接收字符
+    char name[50] = "";
+
+    cout << "请输入姓名: ";
+    // 获取整行的内容,包含空格
+    cin.getline(name, sizeof(name)); //用法: cin.getline(字符数组, 字符数组的长度), 用于获取整行的内容,包含空格
+
+    // 获取输入字符的个数
+    int len = 0;
+    while (name[len++])
+        ;
+    cout << "输入的字符个数为: " << len - 1 << endl;
+
+    return 0;
+}
\ No newline at end of file
diff --git a/day8/d17.cpp b/day8/d17.cpp
new file mode 100644
index 0000000..2eeeea2
--- /dev/null
+++ b/day8/d17.cpp
@@ -0,0 +1,22 @@
+// 从键盘输入5位学生的姓名
+#include <iostream>
+
+using namespace std;
+
+int main()
+{
+    // 键盘输入 5 位学生的姓名
+    char names[5][50] = {""}; // "": 用于初始化字符数组, 也可以写成 "{}"
+    for (int i = 0; i < 5; i++)
+    {
+        cout << "姓名: ";
+        cin.getline(names[i], sizeof(names[i]));
+    }
+
+    for (int i = 0; i < 5; i++)
+    {
+        cout << names[i] << endl;
+    }
+
+    return 0;
+}
\ No newline at end of file
diff --git a/day8/d2.cpp b/day8/d2.cpp
new file mode 100644
index 0000000..e69de29
diff --git a/day8/d5.cpp b/day8/d5.cpp
new file mode 100644
index 0000000..c2eed5c
--- /dev/null
+++ b/day8/d5.cpp
@@ -0,0 +1,21 @@
+#include <iostream>
+#include <cstdlib>
+
+using namespace std;
+
+int main()
+{
+    srand(time(NULL));
+
+    int arr[5];
+    int i = 0;
+    // 生成 5 个随机数并输出
+    while (i < 5)
+    {
+        arr[i] = rand() % 100; // 生成 0~99 之间的随机数: max = 99, min = 0 -> rand() % (max - min + 1) + min
+        cout << "arr[" << i << "] = " << arr[i] << endl;
+        i++;
+    }
+
+    return 0;
+}
\ No newline at end of file
diff --git a/day8/d6.cpp b/day8/d6.cpp
new file mode 100644
index 0000000..ccd2700
--- /dev/null
+++ b/day8/d6.cpp
@@ -0,0 +1,44 @@
+#include <iostream>
+#include <climits> // 作用: 用于获取整型的最大值 INT_MAX
+
+using namespace std;
+
+int main()
+{
+    int arr[10] = {};
+    int sum = 0;       // 总和
+    int max = INT_MIN; // 最大值： 初始化为整型的最小值
+    int min = INT_MAX; // 最小值: 初始化为整型的最大值
+
+    // 输入 10 个数
+    int n = 0;
+    while (n < 10)
+    {
+        cout << "请输入第" << n + 1 << "个数：";
+        cin >> arr[n];
+        n++;
+    }
+
+    // 输出 10 个数
+    int i = 0;
+    while (i < 10)
+    {
+        sum += arr[i]; // 累加求和
+
+        if (arr[i] > max)
+            max = arr[i]; // 更新最大值
+
+        if (arr[i] < min)
+            min = arr[i]; // 更新最小值
+
+        cout << arr[i] << " "; // 输出
+        i++;
+    }
+    cout << endl;
+
+    cout << "平均值为: " << sum / 10 << endl;
+    cout << "最大值为: " << max << endl;
+    cout << "最小值为: " << min << endl;
+
+    return 0;
+}
\ No newline at end of file
diff --git a/day8/d7.cpp b/day8/d7.cpp
new file mode 100644
index 0000000..bb53c9d
--- /dev/null
+++ b/day8/d7.cpp
@@ -0,0 +1,51 @@
+#include <iostream>
+#include <climits> // 作用: 用于获取整型的最大值 INT_MAX
+#include <cstdlib>
+
+using namespace std;
+
+int main()
+{
+    srand(time(NULL));
+    const int N = 5; // 常量: 用于表示数组的长度
+
+    double arr[N] = {};
+    double sum = 0;       // 总和
+    double avg = 0;       // 平均值
+    double max = INT_MIN; // 最大值： 初始化为整型的最小值
+    double min = INT_MAX; // 最小值: 初始化为整型的最大值
+
+    // 输入 N 个数
+    int n = 0;
+    while (n < N)
+    {
+        arr[n] = rand() % 100; // 生成 0~99 之间的随机数: max = 99, min = 0 -> rand() % (max - min + 1) + min
+        n++;
+    }
+
+    // 输出 N 个数
+    int i = 0;
+    while (i < N)
+    {
+        sum += arr[i]; // 累加求和
+
+        if (arr[i] > max)
+            max = arr[i]; // 更新最大值
+
+        if (arr[i] < min)
+            min = arr[i]; // 更新最小值
+
+        cout << arr[i] << " "; // 输出
+
+        avg += arr[i] / 5.0; // 求平均值
+        i++;
+    }
+    cout << endl;
+
+    cout << "N 位同学的C++课程平均值为: " << sum / N << endl;
+    cout << "N 位同学的C++课程最大值为: " << max << endl;
+    cout << "N 位同学的C++课程最小值为: " << min << endl;
+    cout << avg << endl;
+
+    return 0;
+}
\ No newline at end of file
diff --git a/day8/d8.cpp b/day8/d8.cpp
new file mode 100644
index 0000000..6444121
--- /dev/null
+++ b/day8/d8.cpp
@@ -0,0 +1,15 @@
+#include <iostream>
+#include <cstdlib>
+
+using namespace std;
+
+int main()
+{
+    int arr[][3] = {1, 2, 3, 4, 5};
+    // 计算行数
+    int rows = sizeof(arr) / sizeof(arr[0]);
+    cout << "行数: " << rows << endl;
+    cout << "第一行最后一列的值: " << arr[0][2] << endl;
+
+    return 0;
+}
\ No newline at end of file
diff --git a/day8/d9.cpp b/day8/d9.cpp
new file mode 100644
index 0000000..049eaf8
--- /dev/null
+++ b/day8/d9.cpp
@@ -0,0 +1,29 @@
+#include <iostream>
+#include <cstdlib>
+
+using namespace std;
+
+int main()
+{
+    int arr[3][5] = {
+        {1, 2, 3, 4, 5},
+        {10, 20, 30, 40, 50},
+        {100, 200, 300, 400, 500}};
+
+    cout << "第一行数据: ";
+    for (int i = 0; i < 5; i++)
+    {
+        cout << arr[0][i] << "\t";
+    }
+    cout << endl;
+
+    // 读取所有行的数据
+    for (int i = 0; i < 3; i++)
+    {
+        for (int j = 0; j < 5; j++)
+            cout << arr[i][j] << "\t";
+        cout << endl;
+    }
+
+    return 0;
+}
\ No newline at end of file