diff --git a/lec01/hello.c b/lec01/hello.c
new file mode 100644
index 0000000000000000000000000000000000000000..3d156bc2fcf67a8c21dfaac37d2e7a9ab96a5517
--- /dev/null
+++ b/lec01/hello.c
@@ -0,0 +1,6 @@
+#include<stdio.h>
+
+int main()
+{
+	printf("Hello World\n");
+}
diff --git a/lec02/date.txt b/lec02/date.txt
new file mode 100644
index 0000000000000000000000000000000000000000..80f42ccb7f2a028614c3dec1a994a329ca3b5ac8
--- /dev/null
+++ b/lec02/date.txt
@@ -0,0 +1,2 @@
+2022. 01. 05. (수) 16:09:53 KST
+2022. 01. 05. (수) 16:22:33 KST
diff --git a/lec02/err.txt b/lec02/err.txt
new file mode 100644
index 0000000000000000000000000000000000000000..dd8f5cd7bafef663cc825f702390ce096eba2476
--- /dev/null
+++ b/lec02/err.txt
@@ -0,0 +1 @@
+Hello stderr 201723312
diff --git a/lec02/hello.c b/lec02/hello.c
new file mode 100644
index 0000000000000000000000000000000000000000..4af461d3e43b82e08ba78fc2f4faf84d6488e95a
--- /dev/null
+++ b/lec02/hello.c
@@ -0,0 +1,9 @@
+#include<stdio.h>
+
+int main()
+{
+	int in_a;
+	fscanf(stdin, "%d", &in_a);
+	fprintf(stdout, "Hello stdout %d\n", in_a);
+	fprintf(stderr, "Hello stderr %d\n", in_a);
+}
diff --git a/lec02/hello3 b/lec02/hello3
new file mode 100644
index 0000000000000000000000000000000000000000..a611f44fe0a384ea1477ca6de830689e4bfb9e66
--- /dev/null
+++ b/lec02/hello3
@@ -0,0 +1,27 @@
+#include<stdio.h>
+
+int main()
+{
+	FILE *fout;
+	fout = fopen("output.txt","w");
+	fprintf(fout, "Hello World\n");
+	fclose(fout);
+}
+#include<stdio.h>
+
+int main()
+{
+	FILE *fout;
+	fout = fopen("output.txt","w");
+	fprintf(fout, "Hello World\n");
+	fclose(fout);
+}
+#include<stdio.h>
+
+int main()
+{
+	FILE *fout;
+	fout = fopen("output.txt","w");
+	fprintf(fout, "Hello World\n");
+	fclose(fout);
+}
diff --git a/lec02/hello4 b/lec02/hello4
new file mode 100644
index 0000000000000000000000000000000000000000..a611f44fe0a384ea1477ca6de830689e4bfb9e66
--- /dev/null
+++ b/lec02/hello4
@@ -0,0 +1,27 @@
+#include<stdio.h>
+
+int main()
+{
+	FILE *fout;
+	fout = fopen("output.txt","w");
+	fprintf(fout, "Hello World\n");
+	fclose(fout);
+}
+#include<stdio.h>
+
+int main()
+{
+	FILE *fout;
+	fout = fopen("output.txt","w");
+	fprintf(fout, "Hello World\n");
+	fclose(fout);
+}
+#include<stdio.h>
+
+int main()
+{
+	FILE *fout;
+	fout = fopen("output.txt","w");
+	fprintf(fout, "Hello World\n");
+	fclose(fout);
+}
diff --git a/lec02/in.txt b/lec02/in.txt
new file mode 100644
index 0000000000000000000000000000000000000000..86c8b4337746c539e43f9491ef6eea660e8c0cd2
--- /dev/null
+++ b/lec02/in.txt
@@ -0,0 +1 @@
+201723312
diff --git a/lec02/message.txt b/lec02/message.txt
new file mode 100644
index 0000000000000000000000000000000000000000..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
diff --git a/lec02/out.txt b/lec02/out.txt
new file mode 100644
index 0000000000000000000000000000000000000000..490742247379d1c005269e85a0eac322442c51f3
--- /dev/null
+++ b/lec02/out.txt
@@ -0,0 +1 @@
+Hello stdout 201723312
diff --git a/lec02/output.txt b/lec02/output.txt
new file mode 100644
index 0000000000000000000000000000000000000000..557db03de997c86a4a028e1ebd3a1ceb225be238
--- /dev/null
+++ b/lec02/output.txt
@@ -0,0 +1 @@
+Hello World
diff --git a/lec02/total.txt b/lec02/total.txt
new file mode 100644
index 0000000000000000000000000000000000000000..e95deb4c86cdf61e2d5f540fe8da76d825387528
--- /dev/null
+++ b/lec02/total.txt
@@ -0,0 +1,11 @@
+2022. 01. 05. (수) 16:02:16 KST
+#include<stdio.h>
+
+int main()
+{
+	FILE *fout;
+	fout = fopen("output.txt","w");
+	fprintf(fout, "Hello World\n");
+	fclose(fout);
+}
+Hello World