use of initialization list in c++ code example

Example 1: initialization list c++

struct S {
    int n;
    S(int); // constructor declaration
    S() : n(7) {} // constructor definition.
                  // ": n(7)" is the initializer list
};

S::S(int x) : n{x} {} // constructor definition. ": n{x}" is the initializer list

int main() {
    S s; // calls S::S()
    S s2(10); // calls S::S(int)
}

Example 2: initializer list c++

class Example {
public:
	int m_A, m_B, m_C;
	Example(int a, int b, int c);
};

Example::Example(int a, int b, int c):
	// This is an initializer list
	m_A(a),
	m_B(b),
	m_C(c)
{ /* Constructor code */ }