diff --git a/.gitignore b/.gitignore
index 7a042f5..c9a224c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,88 +1,94 @@
-# ---> C++
-# Prerequisites
-*.d
-
-# Compiled Object files
-*.slo
-*.lo
-*.o
-*.obj
-
-# Precompiled Headers
-*.gch
-*.pch
-
-# Compiled Dynamic libraries
-*.so
-*.dylib
-*.dll
-
-# Fortran module files
-*.mod
-*.smod
-
-# Compiled Static libraries
-*.lai
-*.la
-*.a
-*.lib
-
-# Executables
-*.exe
-*.out
-*.app
-
-# ---> C
-# Prerequisites
-*.d
-
-# Object files
-*.o
-*.ko
-*.obj
-*.elf
-
-# Linker output
-*.ilk
-*.map
-*.exp
-
-# Precompiled Headers
-*.gch
-*.pch
-
-# Libraries
-*.lib
-*.a
-*.la
-*.lo
-
-# Shared objects (inc. Windows DLLs)
-*.dll
-*.so
-*.so.*
-*.dylib
-
-# Executables
-*.exe
-*.out
-*.app
-*.i*86
-*.x86_64
-*.hex
-
-# Debug files
-*.dSYM/
-*.su
-*.idb
-*.pdb
-
-# Kernel Module Compile Results
-*.mod*
-*.cmd
-.tmp_versions/
-modules.order
-Module.symvers
-Mkfile.old
-dkms.conf
-
+# ---> C++
+# Prerequisites
+*.d
+
+# Compiled Object files
+*.slo
+*.lo
+*.o
+*.obj
+
+# Precompiled Headers
+*.gch
+*.pch
+
+# Compiled Dynamic libraries
+*.so
+*.dylib
+*.dll
+
+# Fortran module files
+*.mod
+*.smod
+
+# Compiled Static libraries
+*.lai
+*.la
+*.a
+*.lib
+
+# Executables
+*.exe
+*.out
+*.app
+
+# ---> C
+# Prerequisites
+*.d
+
+# Object files
+*.o
+*.ko
+*.obj
+*.elf
+
+# Linker output
+*.ilk
+*.map
+*.exp
+
+# Precompiled Headers
+*.gch
+*.pch
+
+# Libraries
+*.lib
+*.a
+*.la
+*.lo
+
+# Shared objects (inc. Windows DLLs)
+*.dll
+*.so
+*.so.*
+*.dylib
+
+# Executables
+*.exe
+*.out
+*.app
+*.i*86
+*.x86_64
+*.hex
+
+# Debug files
+*.dSYM/
+*.su
+*.idb
+*.pdb
+
+# Kernel Module Compile Results
+*.mod*
+*.cmd
+.tmp_versions/
+modules.order
+Module.symvers
+Mkfile.old
+dkms.conf
+
+# 自定义
+*/output
+*.i
+*.s
+*.o
+*.swp
\ No newline at end of file
diff --git a/day4/d2.cpp b/day4/d2.cpp
new file mode 100644
index 0000000..058e619
--- /dev/null
+++ b/day4/d2.cpp
@@ -0,0 +1,13 @@
+#include <bitset> // 用于使用bitset
+#include <iostream>
+
+using namespace std;
+
+int main()
+{
+    cout << "12 = " << 12 << endl;                      // 结果：12
+    cout << "ob01001 = " << bitset<5>(0b01001) << endl; // 结果：9, bitset<8>用于2进制形式输出
+    cout << "062 = " << 062 << endl;                    // 结果: 50
+    cout << "062 = " << oct << 062 << endl;             // 结果: 50, oct 用于8进制形式输出
+    cout << "0x4f = " << hex << 0x4f << endl;           // 结果: 79，hex 用于16进制形式输出
+}
diff --git a/day4/exercise_2.4.1.cpp b/day4/exercise_2.4.1.cpp
new file mode 100644
index 0000000..c2d9af1
--- /dev/null
+++ b/day4/exercise_2.4.1.cpp
@@ -0,0 +1,13 @@
+#include <bitset> // 用于使用bitset
+#include <iostream>
+
+using namespace std;
+
+int main()
+{
+    int x;
+    x = 52;
+    cout << "52 的二进制:" << bitset<8>(x) << endl; // bitset<8>用于2进制形式输出, 8表示8位
+    cout << "52 的八进制:" << oct << x << endl;     // oct 用于8进制形式输出
+    cout << "52 的十六进制:" << hex << x << endl;   // hex 用于16进制形式输出
+}
diff --git a/day4/hello.cpp b/day4/hello.cpp
new file mode 100644
index 0000000..2cf3a0f
--- /dev/null
+++ b/day4/hello.cpp
@@ -0,0 +1,21 @@
+/* ************************************************************************
+ *       Filename:  hello.cpp
+ *    Description:
+ *        Version:  1.0
+ *        Created:  2023年06月14日 17时37分18秒
+ *       Revision:  none
+ *       Compiler:  gcc
+ *         Author:  YOUR NAME (liubo),
+ *        Company:
+ * ************************************************************************/
+
+#include <iostream>
+
+using namespace std;
+
+int main(int argc, char **argv)
+{
+	// 你好，c++
+	cout << "hi, c++" << endl;
+	return 0;
+}