From 420792d73375fdab332c1f74e68a42045b4bd23c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E7=8E=8B=E5=BC=BA?= <“3108497868@qq.com”> Date: Sun, 27 Nov 2022 14:51:23 +0800 Subject: [PATCH 1/8] =?UTF-8?q?=E7=AC=AC=E4=B8=80=E6=AC=A1=E4=BD=9C?= =?UTF-8?q?=E4=B8=9A?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- ...347\254\254\344\270\200\346\254\241java.md" | 18 ++++++++++++++++++ "45 \347\216\213\345\274\272/javaes_code.java" | 10 ++++++++++ 2 files changed, 28 insertions(+) create mode 100644 "45 \347\216\213\345\274\272/20221124\347\254\254\344\270\200\346\254\241java.md" create mode 100644 "45 \347\216\213\345\274\272/javaes_code.java" diff --git "a/45 \347\216\213\345\274\272/20221124\347\254\254\344\270\200\346\254\241java.md" "b/45 \347\216\213\345\274\272/20221124\347\254\254\344\270\200\346\254\241java.md" new file mode 100644 index 0000000..36f085e --- /dev/null +++ "b/45 \347\216\213\345\274\272/20221124\347\254\254\344\270\200\346\254\241java.md" @@ -0,0 +1,18 @@ +## JDK的下载和使用 + +1.下载jdk + +2.jdk的使用 + +注意不要空格，不要中文 + +3.需要配置环境变量 + +```java +public class HelloWorld{ + public static void main(String[]args){ + System.out.println("Hi MXDX!") + } +} +``` + diff --git "a/45 \347\216\213\345\274\272/javaes_code.java" "b/45 \347\216\213\345\274\272/javaes_code.java" new file mode 100644 index 0000000..b0facbd --- /dev/null +++ "b/45 \347\216\213\345\274\272/javaes_code.java" @@ -0,0 +1,10 @@ +public class javaes_code { + public static void main(String[] args) { + String teacher = "丘丘老师"; + String my = "我"; + System.out.println( my+'说'); + System.out.println( "丘丘老师你傲然而立的姿态，那卓然不群的模样，更能显露出你“学富五车”般的才华!" ); + System.out.println( teacher+'说'); + System.out.println( "你说得对"); + } +} -- Gitee From 3bef75a6156582dc9b841fd215a8c3e848c4d59b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E7=8E=8B=E5=BC=BA?= <“3108497868@qq.com”> Date: Sun, 27 Nov 2022 15:54:53 +0800 Subject: [PATCH 2/8] =?UTF-8?q?=E4=BD=9C=E4=B8=9A=E6=8F=90=E4=BA=A4?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- .../20221124\347\254\254\344\270\200\346\254\241java.md" | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git "a/45 \347\216\213\345\274\272/20221124\347\254\254\344\270\200\346\254\241java.md" "b/45 \347\216\213\345\274\272/20221124\347\254\254\344\270\200\346\254\241java.md" index 36f085e..b70ee49 100644 --- "a/45 \347\216\213\345\274\272/20221124\347\254\254\344\270\200\346\254\241java.md" +++ "b/45 \347\216\213\345\274\272/20221124\347\254\254\344\270\200\346\254\241java.md" @@ -1,4 +1,4 @@ -## JDK的下载和使用 +111111## JDK的下载和使用 1.下载jdk -- Gitee From 671dc041109107e632850ddcc31d491bb4215c1d Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E7=8E=8B=E5=BC=BA?= <“3108497868@qq.com”> Date: Sun, 27 Nov 2022 16:06:56 +0800 Subject: [PATCH 3/8] =?UTF-8?q?=E6=88=91=E7=9A=84=E7=AC=AC=E4=BA=8C?= =?UTF-8?q?=E6=AC=A1=E4=BD=9C=E4=B8=9A?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- ...47\254\254\344\270\200\346\254\241java.md" | 47 +++++++++++++++---- 1 file changed, 39 insertions(+), 8 deletions(-) diff --git "a/45 \347\216\213\345\274\272/20221124\347\254\254\344\270\200\346\254\241java.md" "b/45 \347\216\213\345\274\272/20221124\347\254\254\344\270\200\346\254\241java.md" index b70ee49..a7604a9 100644 --- "a/45 \347\216\213\345\274\272/20221124\347\254\254\344\270\200\346\254\241java.md" +++ "b/45 \347\216\213\345\274\272/20221124\347\254\254\344\270\200\346\254\241java.md" @@ -1,18 +1,49 @@ -111111## JDK的下载和使用 +## 字面量分类 -1.下载jdk +1.字符串字面量 -2.jdk的使用 +2.整数字面量 + +3.小数字面量 + +4.字符字面量 + +5.布尔字面量 + +## 变量 + +变量的注意事项 + +变量名不能重复定义 +变量未赋值，不能使用 +定义long类型变量，数据后面加L +定义float类型变量，数据后面加F + +## 关键字 + +关键字的字母全部小写 + +## 标识符 + +由数字、字母、下划线(_)和美元符($)组成 + +不能以数字开头 +不能是关键字 +区分大小写 -注意不要空格，不要中文 -3.需要配置环境变量 ```java -public class HelloWorld{ - public static void main(String[]args){ - System.out.println("Hi MXDX!") +public class javaes_code { + public static void main(String[] args) { + String teacher = "丘丘老师"; + String my = "我"; + System.out.println( my+'说'); + System.out.println( "丘丘老师你傲然而立的姿态，那卓然不群的模样，更能显露出你“学富五车”般的才华!" ); + System.out.println( teacher+'说'); + System.out.println( "你说得对"); } } ``` + -- Gitee From 2023bbd92be9676fea5f672afe3803e6fd29fecd Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E7=8E=8B=E5=BC=BA?= <“3108497868@qq.com”> Date: Sun, 27 Nov 2022 16:15:18 +0800 Subject: [PATCH 4/8] =?UTF-8?q?=E6=88=91=E7=9A=84=E7=AC=AC=E4=BA=8C?= =?UTF-8?q?=E6=AC=A1=E4=BD=9C=E4=B8=9A?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- ...47\254\254\344\272\214\346\254\241java.md" | 49 +++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 "45 \347\216\213\345\274\272/\347\254\254\344\272\214\346\254\241/20221125\347\254\254\344\272\214\346\254\241java.md" diff --git "a/45 \347\216\213\345\274\272/\347\254\254\344\272\214\346\254\241/20221125\347\254\254\344\272\214\346\254\241java.md" "b/45 \347\216\213\345\274\272/\347\254\254\344\272\214\346\254\241/20221125\347\254\254\344\272\214\346\254\241java.md" new file mode 100644 index 0000000..a7604a9 --- /dev/null +++ "b/45 \347\216\213\345\274\272/\347\254\254\344\272\214\346\254\241/20221125\347\254\254\344\272\214\346\254\241java.md" @@ -0,0 +1,49 @@ +## 字面量分类 + +1.字符串字面量 + +2.整数字面量 + +3.小数字面量 + +4.字符字面量 + +5.布尔字面量 + +## 变量 + +变量的注意事项 + +变量名不能重复定义 +变量未赋值，不能使用 +定义long类型变量，数据后面加L +定义float类型变量，数据后面加F + +## 关键字 + +关键字的字母全部小写 + +## 标识符 + +由数字、字母、下划线(_)和美元符($)组成 + +不能以数字开头 +不能是关键字 +区分大小写 + + + +```java +public class javaes_code { + public static void main(String[] args) { + String teacher = "丘丘老师"; + String my = "我"; + System.out.println( my+'说'); + System.out.println( "丘丘老师你傲然而立的姿态，那卓然不群的模样，更能显露出你“学富五车”般的才华!" ); + System.out.println( teacher+'说'); + System.out.println( "你说得对"); + } +} +``` + + -- Gitee From a39aea0c9cf2cb8688d34d0dc466ee242a073cb9 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E7=8E=8B=E5=BC=BA?= <“3108497868@qq.com”> Date: Sun, 27 Nov 2022 16:18:51 +0800 Subject: [PATCH 5/8] =?UTF-8?q?=E6=88=91=E7=9A=84=E7=AC=AC=E4=BA=8C?= =?UTF-8?q?=E6=AC=A1=E4=BD=9C=E4=B8=9A?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- .../20221125\347\254\254\344\272\214\346\254\241java.md" | 0 1 file changed, 0 insertions(+), 0 deletions(-) rename "45 \347\216\213\345\274\272/\347\254\254\344\272\214\346\254\241/20221125\347\254\254\344\272\214\346\254\241java.md" => "45 \347\216\213\345\274\272/20221125\347\254\254\344\272\214\346\254\241java.md" (100%) diff --git "a/45 \347\216\213\345\274\272/\347\254\254\344\272\214\346\254\241/20221125\347\254\254\344\272\214\346\254\241java.md" "b/45 \347\216\213\345\274\272/20221125\347\254\254\344\272\214\346\254\241java.md" similarity index 100% rename from "45 \347\216\213\345\274\272/\347\254\254\344\272\214\346\254\241/20221125\347\254\254\344\272\214\346\254\241java.md" rename to "45 \347\216\213\345\274\272/20221125\347\254\254\344\272\214\346\254\241java.md" -- Gitee From 38b1a0bce19d4efc321dc979d615c02c71d91fcf Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E7=8E=8B=E5=BC=BA?= <“3108497868@qq.com”> Date: Sun, 27 Nov 2022 16:20:31 +0800 Subject: [PATCH 6/8] =?UTF-8?q?=E6=88=91=E7=9A=84=E7=AC=AC=E4=BA=8C?= =?UTF-8?q?=E6=AC=A1=E4=BD=9C=E4=B8=9A?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- ...47\254\254\344\270\200\346\254\241java.md" | 49 ------------------- 1 file changed, 49 deletions(-) delete mode 100644 "45 \347\216\213\345\274\272/20221124\347\254\254\344\270\200\346\254\241java.md" diff --git "a/45 \347\216\213\345\274\272/20221124\347\254\254\344\270\200\346\254\241java.md" "b/45 \347\216\213\345\274\272/20221124\347\254\254\344\270\200\346\254\241java.md" deleted file mode 100644 index a7604a9..0000000 --- "a/45 \347\216\213\345\274\272/20221124\347\254\254\344\270\200\346\254\241java.md" +++ /dev/null @@ -1,49 +0,0 @@ -## 字面量分类 - -1.字符串字面量 - -2.整数字面量 - -3.小数字面量 - -4.字符字面量 - -5.布尔字面量 - -## 变量 - -变量的注意事项 - -变量名不能重复定义 -变量未赋值，不能使用 -定义long类型变量，数据后面加L -定义float类型变量，数据后面加F - -## 关键字 - -关键字的字母全部小写 - -## 标识符 - -由数字、字母、下划线(_)和美元符($)组成 - -不能以数字开头 -不能是关键字 -区分大小写 - - - -```java -public class javaes_code { - public static void main(String[] args) { - String teacher = "丘丘老师"; - String my = "我"; - System.out.println( my+'说'); - System.out.println( "丘丘老师你傲然而立的姿态，那卓然不群的模样，更能显露出你“学富五车”般的才华!" ); - System.out.println( teacher+'说'); - System.out.println( "你说得对"); - } -} -``` - - -- Gitee From a350b492633b7768f98cf6242cfa1ee2f5251320 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E7=8E=8B=E5=BC=BA?= <“3108497868@qq.com”> Date: Sun, 27 Nov 2022 16:23:32 +0800 Subject: [PATCH 7/8] 123456789 --- "45 \347\216\213\345\274\272/123456789.txt" | 0 1 file changed, 0 insertions(+), 0 deletions(-) create mode 100644 "45 \347\216\213\345\274\272/123456789.txt" diff --git "a/45 \347\216\213\345\274\272/123456789.txt" "b/45 \347\216\213\345\274\272/123456789.txt" new file mode 100644 index 0000000..e69de29 -- Gitee From ee4dcd8b578ca656b1c50d44637677e5ff25118c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E7=8E=8B=E5=BC=BA?= <“3108497868@qq.com”> Date: Wed, 30 Nov 2022 18:27:40 +0800 Subject: [PATCH 8/8] =?UTF-8?q?=E6=88=91=E7=9A=84=E7=AC=AC=E4=B8=89?= =?UTF-8?q?=E6=AC=A1=E4=BD=9C=E4=B8=9A?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- "45 \347\216\213\345\274\272/123456789.txt" | 0 ...72\346\234\254\350\257\255\346\263\225.md" | 111 ++++++++++++++++++ .../javaes_code.java" | 10 -- 3 files changed, 111 insertions(+), 10 deletions(-) delete mode 100644 "45 \347\216\213\345\274\272/123456789.txt" create mode 100644 "45 \347\216\213\345\274\272/20221129java\345\237\272\346\234\254\350\257\255\346\263\225.md" delete mode 100644 "45 \347\216\213\345\274\272/javaes_code.java" diff --git "a/45 \347\216\213\345\274\272/123456789.txt" "b/45 \347\216\213\345\274\272/123456789.txt" deleted file mode 100644 index e69de29..0000000 diff --git "a/45 \347\216\213\345\274\272/20221129java\345\237\272\346\234\254\350\257\255\346\263\225.md" "b/45 \347\216\213\345\274\272/20221129java\345\237\272\346\234\254\350\257\255\346\263\225.md" new file mode 100644 index 0000000..15e92fc --- /dev/null +++ "b/45 \347\216\213\345\274\272/20221129java\345\237\272\346\234\254\350\257\255\346\263\225.md" @@ -0,0 +1,111 @@ +1.创建Scanner对象 + +```java +Scanner sc = new Scanner(System.in);//创建Scanner对象，sc表示变量名，其他均可不变 +``` + +2.接收数据 + +```java +int i = sc.nextInt();//表示将键盘录入的值作为int返回 +``` + +示例 + +```java +import java.util.Scanner; +public class ScannerDemo{ + public static void main(String[]args){ + //创建对象 + Scanner sc = new Scanner(System.in); + //接收数据 + int a = sc.nextInt(); + //输出数据 + System.out.println(a); + } +} +``` + +### 类型转换 + +1、自动类型转换 + +```java +double num = 10;//将int类型的10直接赋值给double类型 +System.out.println(num);//输出10.0 +``` + +2、强制类型转换 + +把一个表示数据范围大的数值或者变量赋值给另一个表示数据范围小的变量。 + +​ 强制类型转换格式：目标数据类型 变量名 = (目标数据类型)值或者变量; + +```java +double num1 = 5.5; +int num2 = (int) num1; // 将double类型的num1强制转换为int类型 +System.out.println(num2); // 输出5（小数位直接舍弃） +``` + +## 运算符 + + 运算符：对常量或者变量进行操作的符号 + +表达式：用运算符把常量或者变量连接起来符合Java语法的式子就可以称为表达式。 + +​ 不同运算符连接的表达式体现的是不同类型的表达式。 + +```java +int a = 10; +int b = 20; +int c = a + b; +``` + ++：是运算符，并且是算术运算符。 + +a + b：是表达式，由于+是算术运算符，所以这个表达式叫算术表达式。 a和b称为操作数 + +/和%的区别：两者都做除法， + +/ 取结果的商 ，% 取结果的余数。 + +整数操作只能得到整数，要想得到小数，必须有浮点数参与运算。 + +```java +int a = 10; +int b = 3; +System.out.println(a / b); // 输出结果 +System.out.println(a % b); // 输出结果 +``` + + + +## 作业 + +```java +import java.util.Scanner; +public static void main(Striang[]args){ + Scanner sc = new Scanner (System.in); + Stytem.out.println("请输入一个四位数"); + int age = sc.nexInt(); + int ge = age%10; + int shi = age/10%10; + int bai = age/100%10; + int qian = age/1000; + System.out.println("整数"+age+"个位数为："+ge+"，十位数为："+shi+"，百位数为："+bai+"，千位数为："+qian); + + +Scanner name = new Scanner(System.in); +System.out.println("请输入华氏度"); +double hua = name.nextInt(); +double q = ((hua-32)*5/9); +System.out.println("摄氏度为"+q); +System.out.println("请输入摄氏度"); +double she = name.nextInt(); +double w = (she*9/5+32); +System.out.println("华氏度为："+w) + +} +``` + + diff --git "a/45 \347\216\213\345\274\272/javaes_code.java" "b/45 \347\216\213\345\274\272/javaes_code.java" deleted file mode 100644 index b0facbd..0000000 --- "a/45 \347\216\213\345\274\272/javaes_code.java" +++ /dev/null @@ -1,10 +0,0 @@ -public class javaes_code { - public static void main(String[] args) { - String teacher = "丘丘老师"; - String my = "我"; - System.out.println( my+'说'); - System.out.println( "丘丘老师你傲然而立的姿态，那卓然不群的模样，更能显露出你“学富五车”般的才华!" ); - System.out.println( teacher+'说'); - System.out.println( "你说得对"); - } -} -- Gitee