myvector.cpp

#include "myvector.h"
MyVector::MyVector(int length_of_vector) {
	init(length_of_vector);
}
void MyVector::init(int length_of_vector){
	allocated_length = length = length_of_vector;
	ptr = (twonum*)malloc(allocated_length*sizeof(twonum));
}
void MyVector::push_back(twonum part){
	if (length == allocated_length){
		ptr = (twonum*)realloc(ptr, 2*allocated_length*sizeof(twonum));
		allocated_length *=2;
	}
	ptr[length] = part;
	length+=1;
}
void MyVector::pop_back(){
	length--;
	if(4*length <= allocated_length){
		ptr = (twonum*)realloc(ptr, allocated_length/2*sizeof(twonum));
	}
}
void MyVector::shrink(int x){
	if (x>=allocated_length) return;
	if (4*x <= allocated_length){
		ptr = (twonum*)realloc(ptr, x*sizeof(twonum));
		allocated_length = x;
	}
	length = x;
}

MyVector::twonum& MyVector::operator[](int index) {
	return ptr[index];
}
void MyVector::free_mem(){
	free(ptr);
	ptr = NULL;
}