From 052934cd5425a594ce99ab3e61590f8c0e36e5c5 Mon Sep 17 00:00:00 2001
From: Andy Zhang <37402126+AnzhiZhang@users.noreply.github.com>
Date: Thu, 24 Oct 2024 15:35:41 +0000
Subject: [PATCH 1/2] let printf understands %c

---
 user/printf.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/user/printf.c b/user/printf.c
index 81787467fa..14cc9db0d8 100644
--- a/user/printf.c
+++ b/user/printf.c
@@ -47,7 +47,7 @@ printptr(int fd, uint64 x) {
     putc(fd, digits[x >> (sizeof(uint64) * 8 - 4)]);
 }
 
-// Print to the given fd. Only understands %d, %x, %p, %s.
+// Print to the given fd. Only understands %d, %x, %p, %c, %s.
 void
 vprintf(int fd, const char *fmt, va_list ap)
 {
@@ -93,6 +93,8 @@ vprintf(int fd, const char *fmt, va_list ap)
         i += 2;
       } else if(c0 == 'p'){
         printptr(fd, va_arg(ap, uint64));
+      } else if(c0 == 'c'){
+        putc(fd, va_arg(ap, int));
       } else if(c0 == 's'){
         if((s = va_arg(ap, char*)) == 0)
           s = "(null)";

From c9a5e7f0f000b31f887beef047075ac2a289a2e1 Mon Sep 17 00:00:00 2001
From: Andy Zhang <37402126+AnzhiZhang@users.noreply.github.com>
Date: Thu, 31 Oct 2024 16:06:12 +0000
Subject: [PATCH 2/2] update kernal/printf.c

---
 kernel/printf.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/printf.c b/kernel/printf.c
index d20534c150..9326608da4 100644
--- a/kernel/printf.c
+++ b/kernel/printf.c
@@ -108,6 +108,8 @@ printf(char *fmt, ...)
       i += 2;
     } else if(c0 == 'p'){
       printptr(va_arg(ap, uint64));
+    } else if(c0 == 'c'){
+      putc(fd, va_arg(ap, int));
     } else if(c0 == 's'){
       if((s = va_arg(ap, char*)) == 0)
         s = "(null)";