diff --git a/README.md b/README.md
index 4d8b90a..fa7869f 100644
--- a/README.md
+++ b/README.md
@@ -55,19 +55,13 @@ chmod +x runner.sh
 ### Linux and macOS
 
 ```bash
-# Run a specific file
-./runner.sh HelloWorld.java
-
-# If there is only one .java file in the current directory, the argument is optional
-./runner.sh
-
-# If no .java file is found in the current directory, runner looks inside examples/ automatically
-./runner.sh
-
-# Enable watch mode: recompiles and reruns every time the file is saved
-./runner.sh HelloWorld.java --watch
-
-# Show help
+./runner.sh HelloWorld.java           # run a specific file
+./runner.sh                           # auto-detect
+./runner.sh HelloWorld.java --watch   # watch mode
+./runner.sh *.java --all              # compile all .java in the directory together
+./runner.sh Main.java --input in.txt  # pipe file into stdin
+./runner.sh Main.java --output out.txt
+./runner.sh Main.java --classpath lib/junit.jar
 ./runner.sh --help
 ```
 
@@ -75,8 +69,10 @@ chmod +x runner.sh
 
 ```cmd
 runner.bat HelloWorld.java
-runner.bat
 runner.bat HelloWorld.java --watch
+runner.bat Main.java --all
+runner.bat Main.java --input in.txt --output out.txt
+runner.bat Main.java --classpath lib\junit.jar
 ```
 
 ### Windows (PowerShell)
@@ -85,12 +81,26 @@ runner.bat HelloWorld.java --watch
 
 ```powershell
 .\runner.ps1 HelloWorld.java
-.\runner.ps1
 .\runner.ps1 HelloWorld.java -Watch
+.\runner.ps1 Main.java -All
+.\runner.ps1 Main.java -InputFile in.txt -OutputFile out.txt
+.\runner.ps1 Main.java -Classpath lib\junit.jar
 ```
 
 ---
 
+## Flags
+
+| Flag | Short form (PS1) | Description |
+|------|-----------------|-------------|
+| `--watch` | `-Watch` | Recompile and rerun every time the file is saved |
+| `--all` | `-All` | Compile all `.java` files in the same directory together |
+| `--input <file>` | `-InputFile <file>` | Pipe a file into stdin when running |
+| `--classpath <path>` | `-Classpath <path>` | Append to the compile and run classpath |
+| `--output <file>` | `-OutputFile <file>` | Save program output to a file (also prints to terminal) |
+
+---
+
 ## File detection order
 
 When no file is passed as an argument, runner searches in this order:
@@ -248,10 +258,10 @@ The `examples/` folder contains three files you can use to verify the setup or a
 
 ### Phase 4 - Features
 
-- [ ] Multi-file support: compile all `.java` files in the current directory together
-- [ ] `--input file.txt` flag to pipe a file into stdin
-- [ ] `--classpath path` flag to append jars to the compile and run commands
-- [ ] `--output file.txt` flag to save program output to a file
+- [x] `--all` flag: compile all `.java` files in the same directory together
+- [x] `--input <file>` flag to pipe a file into stdin
+- [x] `--classpath <path>` flag to append jars to the compile and run commands
+- [x] `--output <file>` flag to save program output to a file (also prints to terminal)
 
 ### Phase 5 - Community
 
diff --git a/runner.bat b/runner.bat
index 6a7c5c6..58fff17 100644
--- a/runner.bat
+++ b/runner.bat
@@ -1,7 +1,7 @@
 @echo off
 REM ─────────────────────────────────────────────────────────────
 REM  java-runner - run Java exercises without an IDE (Windows)
-REM  Usage: runner.bat [File.java] [--watch]
+REM  Usage: runner.bat [File.java] [--watch] [--all] [--input f] [--classpath p] [--output f]
 REM ─────────────────────────────────────────────────────────────
 
 setlocal EnableDelayedExpansion
@@ -17,14 +17,25 @@ set "RESET=[0m"
 
 set "FILE="
 set "WATCH=false"
+set "ALL=false"
+set "INPUT_FILE="
+set "EXTRA_CP="
+set "OUTPUT_FILE="
 
 REM ── Parse arguments ───────────────────────────────────────────
-for %%A in (%*) do (
-  if "%%A"=="--watch" set "WATCH=true"
-  if "%%~xA"==".java" set "FILE=%%A"
-  if "%%A"=="--help" goto :help
-  if "%%A"=="-h" goto :help
-)
+:parse_args
+if "%~1"=="" goto :end_parse
+if /i "%~1"=="--watch"     ( set "WATCH=true"               & shift & goto :parse_args )
+if /i "%~1"=="--all"       ( set "ALL=true"                 & shift & goto :parse_args )
+if /i "%~1"=="--input"     ( shift & set "INPUT_FILE=%~1"   & shift & goto :parse_args )
+if /i "%~1"=="--classpath" ( shift & set "EXTRA_CP=%~1"     & shift & goto :parse_args )
+if /i "%~1"=="--output"    ( shift & set "OUTPUT_FILE=%~1"  & shift & goto :parse_args )
+if /i "%~1"=="--help"      goto :help
+if /i "%~1"=="-h"          goto :help
+if "%~x1"==".java"         ( set "FILE=%~1"                 & shift & goto :parse_args )
+shift
+goto :parse_args
+:end_parse
 
 REM ── Auto-detect .java file ────────────────────────────────────
 if "%FILE%"=="" (
@@ -86,26 +97,49 @@ exit /b
 
 REM ── Help ──────────────────────────────────────────────────────
 :help
-echo Usage: runner.bat [File.java] [--watch]
-echo   File.java   Java file to compile and run
-echo   --watch     Recompile and rerun on every file change
+echo Usage: runner.bat [File.java] [options]
+echo.
+echo Options:
+echo   --watch            Recompile and rerun on every file change
+echo   --all              Compile all .java files in the same directory together
+echo   --input ^<file^>     Pipe file contents into stdin when running
+echo   --classpath ^<path^> Append to the compile and run classpath
+echo   --output ^<file^>    Save program output to file (also prints to terminal)
 exit /b
 
 REM ── Main run function ─────────────────────────────────────────
 :run
   for %%F in ("%FILE%") do set "CLASSNAME=%%~nF"
+  for %%F in ("%FILE%") do set "FILEDIR=%%~dpF"
   set "TMPDIR=%TEMP%\java-runner-%RANDOM%"
   mkdir "%TMPDIR%" 2>nul
 
+  REM Build classpath
+  if defined EXTRA_CP (
+    set "CP=!TMPDIR!;!EXTRA_CP!"
+    set "CP_FLAG=-cp "!EXTRA_CP!""
+  ) else (
+    set "CP=!TMPDIR!"
+    set "CP_FLAG="
+  )
+
   echo.
-  echo !CYAN![....] Compiling %CLASSNAME%.java...!RESET!
+  echo !CYAN![....] Compiling !CLASSNAME!.java...!RESET!
+
+  REM Choose sources: --all compiles every .java in the same directory
+  if "!ALL!"=="true" (
+    set "JAVA_FILES="
+    for %%F in ("!FILEDIR!*.java") do set "JAVA_FILES=!JAVA_FILES! "%%~fF""
+    javac !CP_FLAG! -d "!TMPDIR!" !JAVA_FILES! 2>"!TMPDIR!\errors.txt"
+  ) else (
+    javac !CP_FLAG! -d "!TMPDIR!" "%FILE%" 2>"!TMPDIR!\errors.txt"
+  )
 
-  javac -d "%TMPDIR%" "%FILE%" 2>"%TMPDIR%\errors.txt"
   if errorlevel 1 (
     echo !RED![FAIL] Compilation failed:!RESET!
     echo.
-    type "%TMPDIR%\errors.txt"
-    rmdir /s /q "%TMPDIR%"
+    type "!TMPDIR!\errors.txt"
+    rmdir /s /q "!TMPDIR!"
     exit /b 1
   )
 
@@ -113,9 +147,28 @@ REM ── Main run function ─────────────────
   echo !CYAN!───────────────────────── output ─────────────────────────!RESET!
 
   set "START_TIME=%TIME%"
-  java -cp "%TMPDIR%" "%CLASSNAME%"
-  set "JAVA_EXIT=%ERRORLEVEL%"
-  set "END_TIME=%TIME%"
+
+  REM Run java with optional input and output redirection
+  if defined OUTPUT_FILE (
+    set "TMPOUT=!TMPDIR!\output.txt"
+    if defined INPUT_FILE (
+      java -cp "!CP!" "!CLASSNAME!" < "!INPUT_FILE!" > "!TMPOUT!"
+    ) else (
+      java -cp "!CP!" "!CLASSNAME!" > "!TMPOUT!"
+    )
+    set "JAVA_EXIT=!ERRORLEVEL!"
+    set "END_TIME=!TIME!"
+    type "!TMPOUT!"
+    copy "!TMPOUT!" "!OUTPUT_FILE!" >nul
+  ) else (
+    if defined INPUT_FILE (
+      java -cp "!CP!" "!CLASSNAME!" < "!INPUT_FILE!"
+    ) else (
+      java -cp "!CP!" "!CLASSNAME!"
+    )
+    set "JAVA_EXIT=!ERRORLEVEL!"
+    set "END_TIME=!TIME!"
+  )
 
   REM Parse start time (HH:MM:SS.cc)
   for /f "tokens=1-4 delims=:,. " %%a in ("!START_TIME!") do (
@@ -133,8 +186,9 @@ REM ── Main run function ─────────────────
     echo !RED![FAIL] Finished in !ELAPSED_MS!ms ^(exit code !JAVA_EXIT!^)!RESET!
   ) else (
     echo !GREEN![ OK ] Finished in !ELAPSED_MS!ms!RESET!
+    if defined OUTPUT_FILE echo !CYAN!   Output saved to: !OUTPUT_FILE!!RESET!
   )
   echo.
 
-  rmdir /s /q "%TMPDIR%"
+  rmdir /s /q "!TMPDIR!"
   exit /b !JAVA_EXIT!
diff --git a/runner.ps1 b/runner.ps1
index 4c65009..da1e541 100644
--- a/runner.ps1
+++ b/runner.ps1
@@ -1,16 +1,25 @@
 # java-runner - run Java exercises without an IDE (PowerShell)
-# Usage: .\runner.ps1 [File.java] [-Watch]
+# Usage: .\runner.ps1 [File.java] [-Watch] [-All] [-InputFile f] [-Classpath p] [-OutputFile f]
 
 param(
     [string]$JavaFile = "",
     [switch]$Watch,
+    [switch]$All,
+    [string]$InputFile = "",
+    [string]$Classpath = "",
+    [string]$OutputFile = "",
     [switch]$Help
 )
 
 if ($Help) {
-    Write-Host "Usage: .\runner.ps1 [File.java] [-Watch]"
-    Write-Host "  File.java   Java file to compile and run (optional if only one .java exists)"
-    Write-Host "  -Watch      Recompile and rerun on every file save (event-based)"
+    Write-Host "Usage: .\runner.ps1 [File.java] [options]"
+    Write-Host ""
+    Write-Host "Options:"
+    Write-Host "  -Watch              Recompile and rerun on every file save (event-based)"
+    Write-Host "  -All                Compile all .java files in the same directory together"
+    Write-Host "  -InputFile <file>   Pipe file contents into stdin when running"
+    Write-Host "  -Classpath <path>   Append to the compile and run classpath"
+    Write-Host "  -OutputFile <file>  Save program output to file (also prints to terminal)"
     exit 0
 }
 
@@ -46,14 +55,27 @@ $JavaFile = (Resolve-Path $JavaFile).Path
 
 function Invoke-Run {
     $className = [System.IO.Path]::GetFileNameWithoutExtension($JavaFile)
-    $tmpDir = Join-Path $env:TEMP ("java-runner-" + [System.IO.Path]::GetRandomFileName())
+    $fileDir   = [System.IO.Path]::GetDirectoryName($JavaFile)
+    $tmpDir    = Join-Path $env:TEMP ("java-runner-" + [System.IO.Path]::GetRandomFileName())
     New-Item -ItemType Directory -Path $tmpDir -Force | Out-Null
 
+    # Build classpath
+    $cp = $tmpDir
+    if ($Classpath) { $cp = "$tmpDir;$Classpath" }
+
     Write-Host ""
     Write-Host "[....] Compiling $className.java..." -ForegroundColor Cyan
 
+    # Choose sources: -All compiles every .java in the same directory
     $errFile = Join-Path $tmpDir "errors.txt"
-    & javac -d $tmpDir $JavaFile 2>$errFile
+    if ($All) {
+        $sources = (Get-ChildItem -Path $fileDir -Filter "*.java" -File | ForEach-Object { $_.FullName })
+        $cpArgs  = if ($Classpath) { @("-cp", $Classpath) } else { @() }
+        & javac @cpArgs -d $tmpDir @sources 2>$errFile
+    } else {
+        $cpArgs = if ($Classpath) { @("-cp", $Classpath) } else { @() }
+        & javac @cpArgs -d $tmpDir $JavaFile 2>$errFile
+    }
     $compileExit = $LASTEXITCODE
 
     if ($compileExit -ne 0) {
@@ -68,8 +90,22 @@ function Invoke-Run {
     Write-Host "───────────────────────── output ─────────────────────────" -ForegroundColor Cyan
 
     $sw = [System.Diagnostics.Stopwatch]::StartNew()
-    & java -cp $tmpDir $className
-    $javaExit = $LASTEXITCODE
+
+    # Run with optional input/output redirection
+    if ($InputFile -and $OutputFile) {
+        & java -cp $cp $className < $InputFile | Tee-Object -FilePath $OutputFile
+        $javaExit = $LASTEXITCODE
+    } elseif ($InputFile) {
+        & java -cp $cp $className < $InputFile
+        $javaExit = $LASTEXITCODE
+    } elseif ($OutputFile) {
+        & java -cp $cp $className | Tee-Object -FilePath $OutputFile
+        $javaExit = $LASTEXITCODE
+    } else {
+        & java -cp $cp $className
+        $javaExit = $LASTEXITCODE
+    }
+
     $sw.Stop()
     $elapsed = $sw.ElapsedMilliseconds
 
@@ -78,6 +114,7 @@ function Invoke-Run {
         Write-Host "[FAIL] Finished in ${elapsed}ms (exit code $javaExit)" -ForegroundColor Red
     } else {
         Write-Host "[ OK ] Finished in ${elapsed}ms" -ForegroundColor Green
+        if ($OutputFile) { Write-Host "   Output saved to: $OutputFile" -ForegroundColor Cyan }
     }
     Write-Host ""
 
@@ -88,7 +125,7 @@ function Invoke-Run {
 if ($Watch) {
     Write-Host "[WATCH] Watch mode enabled - save the file to rerun" -ForegroundColor Yellow
 
-    $dir = Split-Path $JavaFile -Parent
+    $dir      = Split-Path $JavaFile -Parent
     $filename = Split-Path $JavaFile -Leaf
 
     Clear-Host
diff --git a/runner.sh b/runner.sh
index 6d835a5..d0c9ee1 100644
--- a/runner.sh
+++ b/runner.sh
@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 # ─────────────────────────────────────────────────────────────
 #  java-runner - run Java exercises without an IDE
-#  Usage: ./runner.sh [File.java] [--watch]
+#  Usage: ./runner.sh [File.java] [--watch] [--all] [--input f] [--classpath p] [--output f]
 # ─────────────────────────────────────────────────────────────
 
 set -euo pipefail
@@ -24,18 +24,33 @@ esac
 # ── Arguments ─────────────────────────────────────────────────
 FILE=""
 WATCH=false
-
-for arg in "$@"; do
-  case $arg in
-    --watch) WATCH=true ;;
-    *.java)  FILE="$arg" ;;
+ALL=false
+INPUT_FILE=""
+EXTRA_CP=""
+OUTPUT_FILE=""
+
+while [[ $# -gt 0 ]]; do
+  case "$1" in
+    --watch)     WATCH=true ;;
+    --all)       ALL=true ;;
+    --input)     INPUT_FILE="$2"; shift ;;
+    --classpath) EXTRA_CP="$2"; shift ;;
+    --output)    OUTPUT_FILE="$2"; shift ;;
     --help|-h)
-      echo -e "Usage: ./runner.sh [File.java] [--watch]"
-      echo -e "  File.java   Java file to compile and run (optional if only one .java exists)"
-      echo -e "  --watch     Recompile and rerun on every file save"
+      echo "Usage: ./runner.sh [File.java] [options]"
+      echo ""
+      echo "Options:"
+      echo "  --watch            Recompile and rerun on every file save"
+      echo "  --all              Compile all .java files in the same directory together"
+      echo "  --input <file>     Pipe file contents into stdin when running"
+      echo "  --classpath <path> Append to the compile and run classpath"
+      echo "  --output <file>    Save program output to file (also prints to terminal)"
       exit 0
       ;;
+    *.java) FILE="$1" ;;
+    *) echo -e "${RED}✗  Unknown argument: $1${RESET}"; exit 1 ;;
   esac
+  shift
 done
 
 # ── Auto-detect .java file ────────────────────────────────────
@@ -71,16 +86,28 @@ fi
 run() {
   local classname
   classname=$(basename "$FILE" .java)
+  local filedir
+  filedir=$(dirname "$FILE")
   local tmpdir
   tmpdir=$(mktemp -d)
 
+  # Build classpath
+  local cp="$tmpdir"
+  [[ -n "$EXTRA_CP" ]] && cp="$cp:$EXTRA_CP"
+
   echo -e ""
   echo -e "${CYAN}▶  Compiling ${classname}.java...${RESET}"
 
-  # Compile - capture errors
-  if ! javac -d "$tmpdir" "$FILE" 2>"$tmpdir/errors.txt"; then
+  # Choose sources: --all compiles every .java in the same directory
+  local sources
+  if $ALL; then
+    sources=("$filedir"/*.java)
+  else
+    sources=("$FILE")
+  fi
+
+  if ! javac ${EXTRA_CP:+-cp "$EXTRA_CP"} -d "$tmpdir" "${sources[@]}" 2>"$tmpdir/errors.txt"; then
     echo -e "${RED}✗  Compilation failed:${RESET}\n"
-    # Strip absolute path noise
     sed "s|$PWD/||g" "$tmpdir/errors.txt"
     rm -rf "$tmpdir"
     return 1
@@ -92,14 +119,28 @@ run() {
   # Run and measure time
   local start
   start=$(date +%s%N 2>/dev/null || date +%s)
+
+  local java_exit
   set +e
-  java -cp "$tmpdir" "$classname"
-  local java_exit=$?
+  if [[ -n "$INPUT_FILE" && -n "$OUTPUT_FILE" ]]; then
+    java -cp "$cp" "$classname" < "$INPUT_FILE" | tee "$OUTPUT_FILE"
+    java_exit=${PIPESTATUS[0]}
+  elif [[ -n "$INPUT_FILE" ]]; then
+    java -cp "$cp" "$classname" < "$INPUT_FILE"
+    java_exit=$?
+  elif [[ -n "$OUTPUT_FILE" ]]; then
+    java -cp "$cp" "$classname" | tee "$OUTPUT_FILE"
+    java_exit=${PIPESTATUS[0]}
+  else
+    java -cp "$cp" "$classname"
+    java_exit=$?
+  fi
   set -e
+
   local end
   end=$(date +%s%N 2>/dev/null || date +%s)
 
-  # Calculate elapsed (nanoseconds if available, else seconds)
+  # Calculate elapsed
   local elapsed
   if [[ ${#start} -gt 10 ]]; then
     elapsed=$(( (end - start) / 1000000 ))
@@ -108,6 +149,7 @@ run() {
       echo -e "${RED}✗  Finished in ${elapsed}ms (exit code ${java_exit})${RESET}\n"
     else
       echo -e "${GREEN}✓  Finished in ${elapsed}ms${RESET}\n"
+      [[ -n "$OUTPUT_FILE" ]] && echo -e "${CYAN}   Output saved to: ${OUTPUT_FILE}${RESET}"
     fi
   else
     elapsed=$(( end - start ))
@@ -116,6 +158,7 @@ run() {
       echo -e "${RED}✗  Finished in ${elapsed}s (exit code ${java_exit})${RESET}\n"
     else
       echo -e "${GREEN}✓  Finished in ${elapsed}s${RESET}\n"
+      [[ -n "$OUTPUT_FILE" ]] && echo -e "${CYAN}   Output saved to: ${OUTPUT_FILE}${RESET}"
     fi
   fi