NSNumber

数值对象和数字的转换

NSNumber *numObj = [NSNumber numberWithInt: 2];

NSInteger myInteger = [numObj integerValue];

int a = [numObj intValue];

//浮点数值使用CGFloat,NSDecimalNumber对象进行处理:

NSDecimalNumber *myDecimalObj = [[NSDecimalNumber alloc] initWithString:@"23.30"]; 

CGFloat myCGFloatValue = 43.4; 

NSDecimalNumber *myOtherDecimalObj = [[NSDecimalNumber alloc] initWithFloat:myCGFloatValue]; 

for(NSString *employee in array)

{}

NSEnumerator *enumerator = [array objectEnumerator];

id obj;

while(obj = [enumerator nextObject])

{}

for(int i = 0;i<[array count];i++)

{}