1、NSNumber是面向对象的,如果使用非面向对象的类,可以使用NSInteger、NSUInteger、CGFloat、double
2、实例化、使用
NSNumber *signedNumber = [NSNumber numberWithInteger:-123456];
NSNumber *unsignedNumber = [NSNumber numberWithUnsignedInteger:123456];
NSNumber *floatNumber = [NSNumber numberWithFloat:123.123456f];
NSNumber *doubleNumber = [NSNumber numberWithDouble:123.1234567890];
NSInteger signedValue = [signedNumber integerValue];
NSUInteger unsignedValue = [unsignedNumber unsignedIntegerValue];
CGFloat floatValue = [floatNumber floatValue];
double doubleValue = [doubleNumber doubleValue];