字符串处理函数

#import <Foundation/Foundation.h>
int main(int argc,const char *argv[])
{
	NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

	NSDate *date = [NSDate date];
	NSLog(@"%@",date);

	NSDate *yestoday = [NSDate dateWithTimeIntervalSinceNow: -(24*60*60)];
	NSLog(@"yestoday is　%@",yestoday);

		  
	NSString *myString = @"123456";
	double doublestring = [myString floatValue];
	NSLog(@"float value:%f",doublestring);
	int intString = [myString intValue];
	NSLog(@"int value:%d",intString);

	int strLen = [myString length];
	NSLog(@"string length:%d",myString);

	NSString *string1 = @"abcdefgh";
	NSString *upper = [string1 uppercaseString];
	NSLog(@"upperString:%@",upper);

	NSString *lower = [string1 lowercaseString];
	NSLog(@"lowerString:%@",lower);

	NSString *numberString = @"one two three";
	NSString *aString = [numberString substringToIndex:3];
	NSLog(@"astring:%@",aString);

	NSRange range = NSMakeRange(4,3);
	NSString *aString2 = [numberString substringWithRange:range];
	NSLog(@"astring2:%@",aString2);

	NSString *numberString2 = @"one two three";
	NSString *aString3 = [numberString2 substringFromIndex:6];
	NSLog(@"astring:%@",aString3);

	NSArray *arr = [numberString componentsSeparatedByString:@""];
	NSLog(@"split into array:%@",arr);

	NSRange foundRange = [numberString rangeOfString:@"two"];
	//NSLog(@"return range:%@",foundRange);

	NSString *string2 = [numberString2 stringByAppendingString:@" four"];
	NSLog(@"appending string:%@",string2);

	NSString *fileContent = [NSString stringWithContentsOfFile:@"gcc.sh"];
	NSLog(@"show file content:%@",fileContent);
	
	NSString *fileName = @"gcc.sh";
	NSString *fileExtension = [fileName pathExtension];
	NSLog(@"show file extension:%@",fileExtension);

	NSURL *url = [NSURL URLWithString:@"http://www.baidu.com/"];
	NSString *urlContent = [NSString stringWithContentsOfURL:url];
	NSLog(@"show url content:%@",urlContent);





}