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fn main() {
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let s1 = gives_ownership(); // gives_ownership moves its return
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// value into s1
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let s2 = String::from("hello"); // s2 comes into scope
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let s3 = takes_and_gives_back(s2); // s2 is moved into
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// takes_and_gives_back, which also
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// moves its return value into s3
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} // Here, s3 goes out of scope and is dropped. s2 was moved, so nothing
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// happens. s1 goes out of scope and is dropped.
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fn gives_ownership() -> String { // gives_ownership will move its
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// return value into the function
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// that calls it
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let some_string = String::from("yours"); // some_string comes into scope
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some_string // some_string is returned and
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// moves out to the calling
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// function
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}
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// 该函数将传入字符串并返回该值
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fn takes_and_gives_back(a_string: String) -> String {
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// a_string comes into
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// scope
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a_string // 返回 a_string 并移出给调用的函数
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}
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