C++ Tips - Part 01

My C++ Tips

Part 01

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std::vector< bool >

• special vector
• space-efficient vector
• each element occupies a SINGLE BIT instead of sizeof(bool) bytes.
• std::vector<bool> is not contiguous

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Narrowing conversion (with std::initializer_list)

float f = 3.14f;
int i = f;  // narrowing: decimal part is lost

double d = 3.45678314;
float fx = d; // narrowing: precision (might) loss

//Narrowing and std::initializer_list
int x1 = 3.14; // OK
int x2{3.14}; // ERROR

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Example of func pointer

using func = int(int);
int foo(int) { return 0; }

int main() 
{
	func* fp = &foo;
	int (*fpp)(int) = &foo;
}