How to use lambda for std::find_if

Question

I am trying to use std::find_if to find an object that matches some criteria. Consider the following:

struct MyStruct         
{
    MyStruct(const int & id) : m_id(id) {}                      
    int m_id;
};
...         
std::vector<MyStruct> myVector; //... assume it contains things

MyStruct toFind(1);
std::vector<MyStruct>::iterator i = std::find_if(myVector.begin(), myVector.end(), ???);

I am not sure what to put in the ???

All the examples I have seen have a lambda that uses a hard-coded value to check for the ID. What I want is to return the iterator/success only if the id of toFind matches the id of one of the items in the vector.

All the examples I have see don't show me how to pass the two parameters

EDIT

Additional info There are two different scenarios I have to use this for One in which there is an == operator for the struct and another in which there is no operator == for the struct - and i can't create one because the criteria for finding a match for this scenario is not as rigid as would be used for an equivalence operator.

(And thanks to all who responded; I was able to use find() in one case and with your help was able to use find_if() for the other)

Answer 1

Try this:

std::find_if(
    myVector.begin(), myVector.end(),
    [&toFind](const MyStruct& x) { return x.m_id == toFind.m_id;});

Alternatively, if you had defined an appropriate == overload for MyStruct, you could just use find:

std::find(myVector.begin(), myVector.end(), toFind);  // requires ==

The find_if version is usually best when you have some kind of heterogeneous lookup, for example if you were just given an int, not a value of MyStruct.