下列可用作C标识符的一组字符序列是（ ）。
A: S.b，sum，average，_above
B: class，day，lotus_1，2day
C:
D: md，&12x，month，student_n!
E: D56，r_1_2，name，_st_1
A: S.b，sum，average，_above
B: class，day，lotus_1，2day
C:
D: md，&12x，month，student_n!
E: D56，r_1_2，name，_st_1
举一反三
- 下列字符序列中,可用作C标识符的一组字符序列是() A: bsumaverage_above B: classdaylotus_12day C: #md&12xmonthstudent_n! D: D56r_1_2name_st_1
- 类MyDate定义如下： class MyDate{ int year=2019, month=5, day=30; { year=2017; month=1; day = 1; } MyDate(int year, int month, int day){this.year=year; this.month=month; this.day=day;} MyData(){this(2018,12,31);} }; 执行语句 MyDate adate=new MyDate(); adate.year、adate.month、adate.day的值为_____________。 A: 2019 5 30 B: 2017 1 1 C: 2018 12 31 D: 不确定不确定不确定
- 将\(f(x) = {1 \over {1 + {x^2}}}\)展开成\(x\)的幂级数为( )。 A: \({1 \over {1 + {x^2}}} = \sum\limits_{n = 0}^\infty { { {( - 1)}^n}{x^{2n}}} \matrix{ {} & {} \cr } ( - \infty < x < + \infty )\) B: \({1 \over {1 + {x^2}}} = \sum\limits_{n = 0}^\infty { { {( - 1)}^n}{x^{2n}}} \matrix{ {} & {} \cr } ( - 1< x < 1)\) C: \({1 \over {1 + {x^2}}} = \sum\limits_{n = 0}^\infty { { {( - 1)}^n}{x^{2n}}} \matrix{ {} & {} \cr } ( - 1 < x < 1)\) D: \({1 \over {1 + {x^2}}} = \sum\limits_{n = 0}^\infty { { x^{2n}}} \matrix{ {} & {} \cr } ( - 1 < x < 1)\)
- 【多选题】下面是R表达式 attributes(airquality) 的运行结果: $names [1] "Ozone" "Solar.R" "Wind" "Temp" "Month" "Day" $class [1] "data.frame" $row.names [1] 1 2 3 4 5 6 7 8 9 10 11 12
- 下列字符序列中,可用作C标识符的一组字符序列是().