书上源码,问题见注释,谢谢!!!!!//Fraction.h
@interface Fraction: NSObject
{
int numerator;
int denominator;
}@property int numerator, denominator;-(void) print;
-(double) convertToNum;
@end
//Fraction.m
#import "Fraction.h" @implementation Fraction
@synthesize numerator, denominator;
-(void) print
{
NSLog (@"%i/%i", numerator, denominator);
}
-(double) convertToNum
{
if (denominator != 0)
return (double) numerator / denominator;
else
return 1.0;
}
@end
#import <Foundation/Foundation.h>#import "Fraction.h"
int main (int argc, const char * argv[])
{
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; // insert code here...
Fraction *myFraction = [[Fractionalloc] init];
[Fraction numerator:100]; //这两句有问题
[Fraction denominator:200];//这两句有问题 NSLog(@"%d %d",[Fraction numerator],[Fraction denominator]); //把上面那两句注释掉可以输出结果 [pool drain];
return 0;
}
为什么无法为变量赋值?????????
[myFraction denominator:200];//这两句有问题
myFraction. denominator = 200;
属性的调用和赋值用点号,中括号是调用方法的:[myFraction 方法];
myFraction. denominator = 200;
或者[myFraction setNumerator]
[myFraction setDenominator]