diff --git a/5/io/fmemopen.c b/5/io/fmemopen.c
new file mode 100644
index 0000000..33221da
--- /dev/null
+++ b/5/io/fmemopen.c
@@ -0,0 +1,6 @@
+#include <stdio.h>
+
+int main(void) {
+  // TODO
+  return 0;
+}
diff --git a/5/io/fopen.c b/5/io/fopen.c
new file mode 100644
index 0000000..a262420
--- /dev/null
+++ b/5/io/fopen.c
@@ -0,0 +1,45 @@
+#include <fcntl.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#define RWRR S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH
+
+int main(void) {
+  
+  int fd = open("test/filefp", O_RDWR | O_CREAT | O_TRUNC, RWRR);
+  
+  if(fd == -1) {
+    printf("open file error filefp\n");
+    return -1;
+  }
+
+  FILE *fp = fdopen(fd, "w+");
+  char buf[1024];
+  
+  if(setvbuf(fp, buf, _IOFBF, 1024)) {
+    printf("setvbuf error\n");
+    return -1;
+  }
+
+  if(ferror(fp)) {
+    printf("io stream error\n");
+    return -1;
+  }
+
+  if(feof(fp)) {
+    printf("arrive the end of the file\n");
+  }
+
+  putc('H', fp);
+  fputc('Y', fp);
+
+  fputs(" Hello World!", fp);
+
+  fflush(fp);
+
+  fclose(fp);
+
+  close(fd);
+
+  return 0;
+}
diff --git a/5/io/fread.c b/5/io/fread.c
new file mode 100644
index 0000000..494cc16
--- /dev/null
+++ b/5/io/fread.c
@@ -0,0 +1,40 @@
+#include <stdio.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+
+int main(void) {
+  FILE *fp = fopen("./test/filefp", "r+");
+
+  char buf[1024];
+
+  char *pbuf = fgets(buf, 1024, fp);
+  
+  printf("buf: %s\n", buf);
+
+  fseek(fp, 0, SEEK_END);
+
+  fprintf(fp, "num: %d", 123456);
+  
+  fpos_t off;
+
+  fgetpos(fp, &off);
+
+  printf("off: %lu\n", off);
+
+  int fd = fileno(fp);
+  
+  struct stat st;
+
+  if(fstat(fd, &st) < 0) {
+    printf("stat error fd\n");
+    return -1;
+  }
+  
+  printf("dev: %ld\n", st.st_dev);
+
+  fclose(fp);
+  close(fd);
+
+  return 0;
+}
diff --git a/5/io/test/filefp b/5/io/test/filefp
new file mode 100644
index 0000000..9b3a0d5
--- /dev/null
+++ b/5/io/test/filefp
@@ -0,0 +1 @@
+HY Hello World!num: 123456num: 123456num: 123456
\ No newline at end of file
diff --git a/5/io/tmpfile.c b/5/io/tmpfile.c
new file mode 100644
index 0000000..370e851
--- /dev/null
+++ b/5/io/tmpfile.c
@@ -0,0 +1,34 @@
+#include <stdio.h>
+
+int main(void) {
+  char buf[L_tmpnam];
+ 
+  char *pbuf = tmpnam(buf);
+
+  printf("tmpnam: %s\n", pbuf);
+
+  FILE *fp = tmpfile();
+  
+  if(fp == NULL) {
+    printf("create tmp file error\n");
+    return -1;
+  }
+
+  fputs("Hellow World!", fp);
+  rewind(fp);
+  
+  char buf2[1024];
+
+  if(fgets(buf2, sizeof(buf2), fp) == NULL){
+    printf("fgets error\n");
+    return -1;
+  }
+
+  fputs(buf2, stdout);
+
+  fclose(fp);
+
+
+
+  return 0;
+}