Added File IO in Objective-C

archive/o/objective-c/README.md

@@ -4,18 +4,20 @@ Welcome to Sample Programs in Objective-C!
 
 ## Sample Programs
 
+- [Capitalize in Objective-C](https://github.com/TheRenegadeCoder/sample-programs/issues/1474)
 - [Hello World in Objective-C](https://therenegadecoder.com/code/hello-world-in-objective-c/)
 - [Even Odd in Objective-C](https://github.com/TheRenegadeCoder/sample-programs/issues/1486)
 - [Factorial](factorial.m)
 - [Fibonacci in Objective-C](https://github.com/TheRenegadeCoder/sample-programs/blob/master/archive/o/objective-c/fribonacci.m)
+- [File IO in Objective-C](https://github.com/TheRenegadeCoder/sample-programs/issues/1482)
 - [Fizz Buzz in Objective-C](https://github.com/TheRenegadeCoder/sample-programs/issues/1492)
 - [Reverse a String in Objective-C](reverse-string.m)
 - [Merge sort in Objective-C](merge-sort.m)
-- [Capitalize in Objective-C](https://github.com/TheRenegadeCoder/sample-programs/issues/1474)
 
 ## Fun Facts
 
 - Debut: 1984
+- Objective-C is a superset of C, any C program can be compiled with an Objective-C compiler.
 
 ## References
 

archive/o/objective-c/file-io.m

@@ -0,0 +1,66 @@
+#import <Foundation/Foundation.h>
+
+NSString* readFileWith(NSString* path) {
+  NSFileHandle* fileHandle = [NSFileHandle fileHandleForReadingAtPath:path];
+  if (fileHandle) {
+    @try {
+      NSData* fileData  = [fileHandle availableData];
+      return [[NSString alloc] initWithBytes:[fileData bytes] length:[fileData length] encoding:NSUTF8StringEncoding];
+    } @catch (NSException *e) {
+      NSLog(@"Error reading file %@", e);
+      return nil;
+    }
+    @finally{
+      [fileHandle closeFile];
+    }
+  }else{
+    NSLog(@"File to read not found %@", path);
+  }
+
+};
+
+BOOL writeFileWith(NSString* path, NSString* content) {
+  NSFileHandle* fileHandle = [NSFileHandle fileHandleForWritingAtPath:path];
+  if(fileHandle){
+    @try {
+      NSData* fileData  = [content dataUsingEncoding:NSUTF8StringEncoding];
+      [fileHandle writeData:fileData];
+      return YES;
+    } @catch (NSException *e) {
+      NSLog(@"Error writing file %@", e);
+      return NO;
+    }
+    @finally{
+      [fileHandle closeFile];
+    }
+  }else{
+    NSLog(@"File to write not found %@", path);
+  }
+
+};
+
+BOOL createFileIfNotExistsAt(NSString* path) {
+  return [[NSFileManager defaultManager] createFileAtPath:path contents:nil attributes:nil];
+};
+
+int main(int argc, const char * argv[]) {
+  @autoreleasepool {
+
+    NSString* path = @"output.txt";
+    if(createFileIfNotExistsAt(path)){
+      BOOL result = writeFileWith(path, @"Hello!");
+      if (result) {
+        NSString* contents = readFileWith(path);
+        if (contents) {
+          NSLog(@"%@", contents);
+        }
+      }
+    }else{
+      NSLog(@"Unable to create file at %@", path);
+    }
+
+    return 0;
+
+  }
+  return 0;
+}