diff --git a/code/machine/console.cc b/code/machine/console.cc
index f122beb..a95973a 100644
--- a/code/machine/console.cc
+++ b/code/machine/console.cc
@@ -173,10 +173,12 @@ ConsoleOutput::PutChar(char ch)
 }
 
 void
-ConsoleOutput::PutString(char *str)
+ConsoleOutput::PutInt(int value)
 {
     ASSERT(putBusy == FALSE);
-    WriteFile(writeFileNo, str, strlen(str));
+    char *printStr = (char*)malloc(sizeof(char)*15);
+    sprintf(printStr, "%d\n", value);
+    WriteFile(writeFileNo, printStr, strlen(printStr)*sizeof(char));
     putBusy = TRUE;
     kernel->interrupt->Schedule(this, ConsoleTime, ConsoleWriteInt);
 }
\ No newline at end of file
diff --git a/code/machine/console.h b/code/machine/console.h
index 03226e9..2047594 100644
--- a/code/machine/console.h
+++ b/code/machine/console.h
@@ -76,7 +76,7 @@ class ConsoleOutput : public CallBackObj {
     void PutChar(char ch);	// Write "ch" to the console display, 
 				// and return immediately.  "callWhenDone" 
 				// will called when the I/O completes. 
-    void PutString(char *str);
+    void PutInt(int n);
     void CallBack();		// Invoked when next character can be put
 				// out to the display.
 
diff --git a/code/machine/interrupt.cc b/code/machine/interrupt.cc
index 7c5027f..96ff68b 100644
--- a/code/machine/interrupt.cc
+++ b/code/machine/interrupt.cc
@@ -359,3 +359,8 @@ Interrupt::DumpState()
     cout << "\nEnd of pending interrupts\n";
 }
 
+void 
+Interrupt::PrintInt(int value)
+{
+    return kernel->PrintInt(value);
+}
\ No newline at end of file
diff --git a/code/threads/kernel.cc b/code/threads/kernel.cc
index 621044c..da8bdd0 100644
--- a/code/threads/kernel.cc
+++ b/code/threads/kernel.cc
@@ -308,4 +308,7 @@ int Kernel::CreateFile(char *filename)
 	return fileSystem->Create(filename);
 }
 
-
+void Kernel::PrintInt(int value)
+{
+    return synchConsoleOut->PutInt(value);
+}
diff --git a/code/threads/kernel.h b/code/threads/kernel.h
index 0f13c5a..9a42aad 100644
--- a/code/threads/kernel.h
+++ b/code/threads/kernel.h
@@ -42,7 +42,9 @@ class Kernel {
 
     void ConsoleTest();         // interactive console self test
     void NetworkTest();         // interactive 2-machine network test
-    Thread* getThread(int threadID){return t[threadID];}    
+    Thread* getThread(int threadID){return t[threadID];}
+
+    void PrintInt(int n);    
     
     int CreateFile(char* filename); // fileSystem call
 
diff --git a/code/userprog/ksyscall.h b/code/userprog/ksyscall.h
index bf1b9f3..6b315f7 100644
--- a/code/userprog/ksyscall.h
+++ b/code/userprog/ksyscall.h
@@ -37,33 +37,7 @@ int SysCreate(char *filename)
 }
 
 void SysPrintInt(int value) {
-  static char zero[2] = "0";
-
-  if (value == 0) {
-    kernel->synchConsoleOut->PutString(zero);
-    return;
-  }
-
-  char outputBuf[INT_BUF_LENGTH];
-  bool isNeg = false;
-  int curPos = INT_BUF_LENGTH;
-  outputBuf[--curPos] = '\0';
-  outputBuf[--curPos] = '\n';
-  
-  if (value < 0) {
-    isNeg = true;
-    value = -value;
-  }
-
-  while (value > 0) {
-    outputBuf[--curPos] = '0' + (value % 10);
-    value /= 10;
-  }
-
-  if (isNeg)
-    outputBuf[--curPos] = '-';
-
-  kernel->synchConsoleOut->PutString(&outputBuf[curPos]);
+  kernel->interrupt->PrintInt(value);
 }
 
 OpenFileId SysOpen(char *name) {
diff --git a/code/userprog/synchconsole.cc b/code/userprog/synchconsole.cc
index b786d7f..aa0e5a6 100644
--- a/code/userprog/synchconsole.cc
+++ b/code/userprog/synchconsole.cc
@@ -107,10 +107,10 @@ SynchConsoleOutput::PutChar(char ch)
 }
 
 void
-SynchConsoleOutput::PutString(char *str)
+SynchConsoleOutput::PutInt(int value)
 {
     lock->Acquire();
-    consoleOutput->PutString(str);
+    consoleOutput->PutInt(value);
     waitFor->P();
     lock->Release();
 }
diff --git a/code/userprog/synchconsole.h b/code/userprog/synchconsole.h
index e412ff2..9c2ff47 100644
--- a/code/userprog/synchconsole.h
+++ b/code/userprog/synchconsole.h
@@ -41,7 +41,7 @@ class SynchConsoleOutput : public CallBackObj {
     ~SynchConsoleOutput();
 
     void PutChar(char ch);	// Write a character, waiting if necessary
-    void PutString(char *ch);
+    void PutInt(int value);
    
   private:
     ConsoleOutput *consoleOutput;// the hardware display