objective_c 第九章课后练习题答案

本章例题比较简单 不再一一列出 

int main(int argc, const char * argv[]) {    @autoreleasepool {//第3题        id dataValue;        XYpoint *myXYpoint=[[XYpoint alloc]init];        [myXYpoint setX:22 andY:33];        dataValue=myXYpoint;        [myXYpoint printf];               //第5题        Fraction *fraction=[[Fraction alloc]init];        Complex *complex=[[Complex alloc]init];        id number=[[Complex alloc]init];                if([fraction isMemberOfClass:[Complex class]]==YES)           NSLog(@"fraction is member of complex class");        if([complex isMemberOfClass:[NSObject class]]==YES)           NSLog(@"complex is member of NSObject class");        if([complex isKindOfClass:[NSObject class]]==YES)           NSLog(@"complex is kind of NSObject ");        if([fraction isKindOfClass:[Fraction class]]==YES)            NSLog(@"fraction is kind of Fraction ");        if([fraction respondsToSelector:@selector(print)]==YES)            NSLog(@"fraction responds to print:method");        if([complex respondsToSelector:@selector(print)]==YES)            NSLog(@"complex responds to print:method");        if([Fraction instancesRespondToSelector:@selector(print)]==YES)            NSLog(@"instances of Fraction respond to print:method ");        if([number respondsToSelector:@selector(print)]==YES)            NSLog(@"instances of number respond to print:method");        if([number isKindOfClass:[complex class]]==YES)            NSLog(@"number is kind of complex");        if([[number class] respondsToSelector:@selector(alloc)]==YES)            NSLog(@"number class respond to alloc method");    }    return 0;}