Objective-C 程序设计（第六版）第七章习题答案

1.各个方法的实现

- (Fraction *) subtract: (Fraction *) f
{
    Fraction *result = [[Fraction alloc] init];
    
    result.numerator = numerator *f.denominator - denominator *f.numerator;
    result.denominator = denominator *f.denominator;
    
    [result reduce];
    return  result;
}

- (Fraction *) multiply: (Fraction *) f
{
    Fraction *result = [[Fraction alloc] init];
    
    result.numerator = numerator *f.numerator;
    result.denominator = denominator *f.denominator;
    
    [result reduce];
    return result;
}

- (Fraction *) divide: (Fraction *) f
{
    Fraction *result = [[Fraction alloc] init];
    
    result.numerator = numerator *f.denominator;
    result.denominator = denominator *f.numerator;
    
    [result reduce];
    return result;
}

2.print方法

- (void) print: (BOOL) isReduce
{
    if (numerator % denominator == 0) {
        NSLog(@"%d",numerator/denominator);
    }else if (isReduce) {
        [self reduce];
        NSLog(@"%d / %d",numerator,denominator);
    }else
        NSLog(@"%d / %d",numerator,denominator);

}

3.对负分数一样使用

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        // insert code here...
        
        Fraction *aFraction = [[Fraction alloc] init];
        Fraction *bFraction = [[Fraction alloc] init];
        Fraction *resultFraction;
        
        [aFraction setTo:-1 over:4];
        [bFraction setTo:-1 over:2];
        
        resultFraction = [aFraction add:bFraction];
        
        
        [resultFraction print:YES];
    }
    return 0;
}

4.

- (void) print: (BOOL) isReduce 
{
    if (numerator % denominator == 0) {
        NSLog(@"%d",numerator/denominator);
    }else if (numerator > denominator){
        [self reduce];
        NSLog(@"%d %d/%d",numerator/denominator,numerator % denominator,denominator);
    }else if (isReduce) {
        [self reduce];
        NSLog(@"%d/%d",numerator,denominator);
    }else
        NSLog(@"%d/%d",numerator,denominator);

}

5.去掉synthesize合成方法后 修改变量名 _numerator, _denominator  替换程序中的numerator,denominator;增加setter方法 用于点语法。

6..m文件

- (Complex *) add: (Complex *) complexNum
{
    Complex *result = [[Complex alloc] init];
    
    result.real = real + complexNum.real;
    result.imaginary = imaginary + complexNum.imaginary;
    
    return result;
}

main

        Complex * aComplex = [[Complex alloc]init];
        Complex * bComplex = [[Complex alloc]init];
        Complex * resultComplex;

        
        [aComplex setReal:5.3];
        [aComplex setImaginary:7];
        [bComplex setReal:2.7];
        [bComplex setImaginary:4];
        resultComplex = [aComplex add:bComplex];
        
        NSLog(@"result is %.f + %.fi",[resultComplex real],[resultComplex imaginary]);
        

7.略吧