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Use C Lambda expressions to customize sorting rules to flexibly define sorting logic. The syntax is: [capture list](parameters) -> return type { body }. In the actual case, the lambda expression sortLambda sorts by string length, and the output is: dog, apple, banana, cherry, elephant.
Use C Lambda expression to customize sorting rules
Lambda expression is an anonymous function that can be used in C to define custom sorting rules. It provides an easy and flexible way to sort your data based on custom logic.
Syntax
The typical lambda expression syntax is as follows:
[capture list](parameters) -> return type { body }
Among them:
capture list
: Optional, used to capture references to external variables. parameters
: Optional, used to obtain input parameters. -> return type
: Optional, used to specify the return type. body
: Function body, containing the code to be executed. Practical case
The following is a practical case using lambda expression to customize sorting rules, which is used to sort a string vector by its length:
#include <iostream> #include <vector> #include <algorithm> using namespace std; int main() { vector<string> strings = {"apple", "banana", "cherry", "dog", "elephant"}; // 定义 lambda 表达式,将字符串按长度排序 auto sortLambda = [](const string& a, const string& b) { return a.length() < b.length(); }; // 使用 lambda 表达式对向量排序 sort(strings.begin(), strings.end(), sortLambda); // 打印排序后的向量 for (const string& s : strings) { cout << s << endl; } return 0; }
Output
dog apple banana cherry elephant
In this example, the lambda expression sortLambda
captures the external variables a
and ## A reference to #b, and returns whether the length of
a is less than the length of
b. The sort function
sort uses this lambda expression to sort a vector of strings in ascending order of their length.
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