代码清单纯3-4 修改而来

最新推荐文章于 2024-05-06 00:00:00 发布

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本文介绍了一个简单的Objective-C分数类的实现，包括设置分子、分母的方法及打印分数的功能。通过实例演示了如何创建分数对象并展示其值。

#import <Foundation/Foundation.h>


//---- @interface ---
@interface Fraction: NSObject

-(void) print;
-(void) setNumerator: (int) n;
-(void) setDenominator: (int) d;

@end

//---- @implementation block ---
@implementation Fraction
{
    int numerator;
    int denominator;
}

-(void) print {
    NSLog(@"%i/%i", numerator, denominator);
}

-(void) setNumerator:(int)n {
    numerator = n;
}

-(void) setDenominator:(int)d {
    denominator = d;
}

-(int) numerator {
    return numerator;
}

-(int) denominator {
    return denominator;
}

@end


int main(int argc, const char * argv[])
{

    @autoreleasepool {
        
        // insert code here...
        //NSLog(@"Hello, World!");
        //NSLog(@"In Objective-C, lowercase letters are significant.\nmain is where program execution begins.\nOpen and closed braces enclose program statements in a routine.\nAll program statements must be terminated by a semicolon.");
        /*
        int x;
        int y;
        
        x = 87;
        y = 15;
        
        x = x-y;
        NSLog(@"%i", x);
        */
        //分数调用部分，分数类，只能写在前面与c语言类似。
        //Fraction *frac1 = [[Fraction alloc] init];
        Fraction *frac1 = [Fraction new];
        Fraction *frac2 = [[Fraction alloc] init];
        
        [frac1 setNumerator: 2];
        [frac1 setDenominator: 3];
        
        [frac2 setNumerator: 3];
        [frac2 setDenominator: 7];
        /*
        NSLog(@"First fraction is:");
        [frac1 print];
        
        NSLog(@"Second fraction is:");
        [frac2 print];
         */
        NSLog(@"The value of myFraction is: %i/%i",
              [frac1 numerator], [frac1 denominator]);
    }
    return 0;
}

1,类的初始化。的不同。

2, 类方法参数的调用。修改。和返回值。