string和vector是两类最重要的标准库类型 strng表示可变长的字符序列 vector存放某种给定类型对象的可变长序列. 3.1 命名空间的using声明 using namespace::name; //using声明 using std::cin; using std::cout;using std::endl; using namespace std; //using指令 每个using引入一个名字,因此每个名字都必须有自己的using 由于头文件的代码会被拷贝到引用它的文件中,
stl的迭代器非常方便 用于各种算法. 可是一想到vector.我们总是把他当做数组,总喜欢使用下标索引,而不是迭代器. 这里有个问题就是怎样把迭代器转换为索引: #include <vector> typedef std::vector<char *> MYARRAY; // This does the trick inline const int iterator_to_index(MYARRAY &a, MYARRAY::iterator it) { return i
常用类型操作, 如python中的list,turple,dictory等, 更方常编程常用数据的处理. fn main() { let v = vec![, , , , ]; let third: &i32 = &v[]; println!("The third element is {}", third); match v.) { Some(third) => println!("The element is {}", third), No
字符串操作 fn first_word(s: &String) -> usize { let bytes = s.as_bytes(); for (i, &item) in bytes.iter().enumerate() { if item == b' ' { return i; } } s.len() } Because we need to go through the String element by element and check whether a value is
2.2 数据类型 let guess: u32 = "42".parse().expect("Not a number!"); Rust has four primary scalar types: integers, floating-point numbers, Booleans, and characters. 整数类型 u32, bits of space. Additionally, the isize and usize types depend on