3-7下列关于分数类型的说法错误的是( )。 A: 分数对象有明确的分子和分母 B: 分数对象表示的分数不一定是最简分数 C: 可调用Fraction(a,b)函数来创建分数对象 D: Fraction.from_float()函数可将浮点数转换为分数

fraction

growth fraction: 

已知一个分数类Fraction,成员由分子和分母构成,在Fraction类中编写一个方法,实现分数对象之间的相加,下列哪个方法定义是符合 A: +(int)add:(int)n:(int)d B: +(Fraction*)add:(int)n:(int)d C: -(int)add:(Fraction*)f D: –(Fraction*)add:(Fraction*)f

名词解释：filtration fraction

fraction /ˈfrækʃn/

燃耗份额 burnup fraction

下面是实现类fraction(分数)的定义的测试程序,其中重载运算符&#91;<以分数形式给出结果。例如将三分之二输出为2/3。 #include< &#93;[br][/br] class fraction{[br][/br] int den, num; public: fraction( int y, int x ) { den=y; num=x; } ostream &operator<<(ostream &s,fraction fr); }; ostream &operator<<(ostream &s,fraction fr) {s<<fr.den<<'/'<<fr.num; return ; } void main() { fraction f(2,3); cout<<f<<endl; }

下面是实现类fraction(分数)的定义的测试程序,其中重载运算符<<以分数形式给出结果。例如将三分之二输出为2/3。 #include &#91;1&#93; class fraction{ int den,num; public: fraction( int y, int x ) { den=y; num=x; }; &#91;2&#93; ostream &operator<<(ostream &s,fraction fr); }; ostream &operator<<(ostream &s,fraction fr) { s<<fr.den<<'/'<<fr.num; return &#91;3&#93; ; } void main() { fraction f(2,3); cout<<f<<endl; }

Pick up the correct statement from the following: A: The distance between two successive crests or troughs of a wave, is called, the wave length B: The wave length is measured in metres and a fraction of a metre C: The wave length is generally denoted by λ D: The length of the crest from the midpoint, is called amplitude E: All of