时间:2019-05-06 标签:c++find_iflambda

What is wrong with the code below? It is supposed to find an element in the list of structs if the first of the struct's members equals to 0. The compiler complains about the lambda argument not being of type predicate.

#include <iostream>
#include <stdint.h>
#include <fstream>
#include <list>
#include <algorithm>

struct S
{
    int S1;
    int S2;
};

using namespace std;

int main()
{
    list<S> l;
    S s1;
    s1.S1 = 0;
    s1.S2 = 0;
    S s2;
    s2.S1 = 1;
    s2.S2 = 1;
    l.push_back(s2);
    l.push_back(s1);

    list<S>::iterator it = find_if(l.begin(), l.end(), [] (S s) { return s.S1 == 0; } );
}

推荐答案

代码在 VS2012 上工作正常，只是一个建议，按引用传递对象而不是按值传递:

list<S>::iterator it = find_if(l.begin(), l.end(), [] (const S& s) { return s.S1 == 0; } );