C++ Syntax Cheatsheet ​

Using Lambdas in C++ ​

Structure of a lambda in C++

auto func = [<capture_clause>] (<arguments>) {
	// ...lambda body
};

auto func = [<capture_clause>] (<arguments>) {
	// ...lambda body
};

Capture Clause. A lambda expression begins with a capture clause, which captures variables from its envrionment for use in the lambda expression. A capture clause is specified with [] and should specify the variables being used in the lambda.

There are three specific wildcard types that are useful when specifying capture clauses.

1. [] means the lambda doesn't take any variables from its environment.
2. [=] means that all variables that are used are captured by value.
3. [&] means that all variables that are used are captured by reference.

For example, all of the below capture clauses are equivalent.

[&variable1, variable2]
[&, variable2]
[=, &variable1]

[&variable1, variable2]
[&, variable2]
[=, &variable1]

for Loops ​

vector<int> v = {1, 2, 3, 4};

// Option 1: Index-based for loop
for (auto i = 0; i < v.size(), i++) {
  // ...
}

// Option 2: Range-based for loop
for (auto item : v) {
  // ...
}

vector<int> v = {1, 2, 3, 4};

// Option 1: Index-based for loop
for (auto i = 0; i < v.size(), i++) {
  // ...
}

// Option 2: Range-based for loop
for (auto item : v) {
  // ...
}