使用类别方法重载NSDecimalNumber上的算术运算符

#import <Foundation/Foundation.h>

@interface NSDecimalNumber (Arithmetic)

// 重载加法运算符
+ (NSDecimalNumber *)add:(NSDecimalNumber *)number1 with:(NSDecimalNumber *)number2;

// 重载减法运算符
+ (NSDecimalNumber *)subtract:(NSDecimalNumber *)number1 with:(NSDecimalNumber *)number2;

// 重载乘法运算符
+ (NSDecimalNumber *)multiply:(NSDecimalNumber *)number1 with:(NSDecimalNumber *)number2;

// 重载除法运算符
+ (NSDecimalNumber *)divide:(NSDecimalNumber *)number1 by:(NSDecimalNumber *)number2;

@end

@implementation NSDecimalNumber (Arithmetic)

+ (NSDecimalNumber *)add:(NSDecimalNumber *)number1 with:(NSDecimalNumber *)number2 {
    return [number1 decimalNumberByAdding:number2];
}

+ (NSDecimalNumber *)subtract:(NSDecimalNumber *)number1 with:(NSDecimalNumber *)number2 {
    return [number1 decimalNumberBySubtracting:number2];
}

+ (NSDecimalNumber *)multiply:(NSDecimalNumber *)number1 with:(NSDecimalNumber *)number2 {
    return [number1 decimalNumberByMultiplyingBy:number2];
}

+ (NSDecimalNumber *)divide:(NSDecimalNumber *)number1 by:(NSDecimalNumber *)number2 {
    return [number1 decimalNumberByDividingBy:number2];
}

@end

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        NSDecimalNumber *num1 = [NSDecimalNumber decimalNumberWithString:@"10"];
        NSDecimalNumber *num2 = [NSDecimalNumber decimalNumberWithString:@"5"];
        
        NSDecimalNumber *sum = [NSDecimalNumber add:num1 with:num2];
        NSDecimalNumber *difference = [NSDecimalNumber subtract:num1 with:num2];
        NSDecimalNumber *product = [NSDecimalNumber multiply:num1 with:num2];
        NSDecimalNumber *quotient = [NSDecimalNumber divide:num1 by:num2];
        
        NSLog(@"Sum: %@", sum);
        NSLog(@"Difference: %@", difference);
        NSLog(@"Product: %@", product);
        NSLog(@"Quotient: %@", quotient);
    }
    return 0;
}