一个网站做几个关键词,搭建大数据平台费用,闵行区,图片库网站建设报价11.函数原型有参数时需要填写对应参数进行调用
这里原先call_me函数没有填写参数导致报错 添加一个usize即可
// functions3.rs
// Execute rustlings hint functions3 or use the hint watch subcommand for a hint.fn main() {call_me(10);
}fn call_me(num: u32) {for i i…11.函数原型有参数时需要填写对应参数进行调用
这里原先call_me函数没有填写参数导致报错 添加一个usize即可
// functions3.rs
// Execute rustlings hint functions3 or use the hint watch subcommand for a hint.fn main() {call_me(10);
}fn call_me(num: u32) {for i in 0..num {println!(Ring! Call number {}, i 1);}
}12.函数需要返回值
fn sale_price(price: i32) - i32前面括号内是传入参数类型,后面是返回值类型
// functions4.rs
// Execute rustlings hint functions4 or use the hint watch subcommand for a hint.// This store is having a sale where if the price is an even number, you get
// 10 Rustbucks off, but if its an odd number, its 3 Rustbucks off.
// (Dont worry about the function bodies themselves, were only interested
// in the signatures for now. If anything, this is a good way to peek ahead
// to future exercises!)fn main() {let original_price 51;println!(Your sale price is {}, sale_price(original_price));
}fn sale_price(price: i32) - i32{if is_even(price) {price - 10} else {price - 3}
}fn is_even(num: i32) - bool {num % 2 0
}13.函数隐式返回,不能使用逗号作为默认返回
这里square函数隐式返回num*num,如果加上分号会返回()
// functions5.rs
// Execute rustlings hint functions5 or use the hint watch subcommand for a hint.// I AM NOT DONEfn main() {let answer square(3);println!(The square of 3 is {}, answer);
}fn square(num: i32) - i32 {num * num
}14.使用if编写函数功能
这里使用if判断ab的情况 然后分情况讨论
// if1.rs
// Execute rustlings hint if1 or use the hint watch subcommand for a hint.pub fn bigger(a: i32, b: i32) - i32 {// Complete this function to return the bigger number!// Do not use:// - another function call// - additional variablesif ab {a}else {b}
}// Dont mind this for now :)
#[cfg(test)]
mod tests {use super::*;#[test]fn ten_is_bigger_than_eight() {assert_eq!(10, bigger(10, 8));}#[test]fn fortytwo_is_bigger_than_thirtytwo() {assert_eq!(42, bigger(32, 42));}
}15.嵌套if返回条件
// if2.rs// Step 1: Make me compile!
// Step 2: Get the bar_for_fuzz and default_to_baz tests passing!
// Execute rustlings hint if2 or use the hint watch subcommand for a hint.pub fn foo_if_fizz(fizzish: str) - str {if fizzish fizz {foo} else {if fizzish fuzz{bar}else {baz}}
}// No test changes needed!
#[cfg(test)]
mod tests {use super::*;#[test]fn foo_for_fizz() {assert_eq!(foo_if_fizz(fizz), foo)}#[test]fn bar_for_fuzz() {assert_eq!(foo_if_fizz(fuzz), bar)}#[test]fn default_to_baz() {assert_eq!(foo_if_fizz(literally anything), baz)}
}其中assert_eq!(a,b)是在比较a,b两个数值是否相等,用于做单元测试
16.使用if进行简单应用场景功能实现
自己编写calculate_price_of_apples(price:i32)-i32即可
// quiz1.rs
// This is a quiz for the following sections:
// - Variables
// - Functions
// - If// Mary is buying apples. The price of an apple is calculated as follows:
// - An apple costs 2 rustbucks.
// - If Mary buys more than 40 apples, each apple only costs 1 rustbuck!
// Write a function that calculates the price of an order of apples given
// the quantity bought. No hints this time!// Put your function here!
fn calculate_price_of_apples(price:i32)-i32 {if (price40){return price*2;}return price;}// Dont modify this function!
#[test]
fn verify_test() {let price1 calculate_price_of_apples(35);let price2 calculate_price_of_apples(40);let price3 calculate_price_of_apples(41);let price4 calculate_price_of_apples(65);assert_eq!(70, price1);assert_eq!(80, price2);assert_eq!(41, price3);assert_eq!(65, price4);
}17.利用boolean类型变量做判断
// primitive_types1.rs
// Fill in the rest of the line that has code missing!
// No hints, theres no tricks, just get used to typing these :)fn main() {// Booleans (bool)let is_morning true;if is_morning {println!(Good morning!);}let is_evening false;// let // Finish the rest of this line like the example! Or make it be false!if is_evening {println!(Good evening!);}
}18.判断字符类型
我们在这里只需要填一个字符即可,即使是emjoy
// primitive_types2.rs
// Fill in the rest of the line that has code missing!
// No hints, theres no tricks, just get used to typing these :)fn main() {// Characters (char)// Note the _single_ quotes, these are different from the double quotes// youve been seeing around.let my_first_initial C;if my_first_initial.is_alphabetic() {println!(Alphabetical!);} else if my_first_initial.is_numeric() {println!(Numerical!);} else {println!(Neither alphabetic nor numeric!);}let your_characteru;// Finish this line like the example! Whats your favorite character?// Try a letter, try a number, try a special character, try a character// from a different language than your own, try an emoji!if your_character.is_alphabetic() {println!(Alphabetical!);} else if your_character.is_numeric() {println!(Numerical!);} else {println!(Neither alphabetic nor numeric!);}
}19.获取字符串长度
// primitive_types3.rs
// Create an array with at least 100 elements in it where the ??? is.
// Execute rustlings hint primitive_types3 or use the hint watch subcommand for a hint.fn main() {let a 99999999999999999999999999999999;if a.len() 100 {println!(Wow, thats a big array!);} else {println!(Meh, I eat arrays like that for breakfast.);}
}20.字符串切片
使用引用变量 [leftIndex..rightIndex)区间内切片
// primitive_types4.rs
// Get a slice out of Array a where the ??? is so that the test passes.
// Execute rustlings hint primitive_types4 or use the hint watch subcommand for a hint.#[test]
fn slice_out_of_array() {let a [1, 2, 3, 4, 5];let nice_slice a[1..4];assert_eq!([2, 3, 4], nice_slice)
}
