Question

How to remove all occurrences of an element from a vector in C++

Answer 1

#include <iostream>
#include <vector>

using std::cout;
using std::endl;

int main()
{
	std::vector<int> vec = { 4, 1, 4, 2, 3, 4, 4, 4, 5, 4 };

	std::vector<int>::iterator it = vec.begin();

	while (it != vec.end())
	{
		if (*it == 4)
		{
			it = vec.erase(it);
		}
		else
			it++;
	}

	for (int i : vec)
		cout << i << " ";

	cout << endl;

	return 0;
}

/*
run:

1 2 3 5

*/

 

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Answer 2

#include <iostream>
#include <vector>
#include <algorithm>

using std::cout;
using std::endl;
using std::vector;

void removeAllElements(vector<int> &vec, int element)
{
	vec.erase(std::remove(vec.begin(), vec.end(), element), vec.end());
}

void print(vector<int> &vec)
{
	for (int i : vec)
		cout << i << " ";

	cout << endl;
}

int main()
{
	vector<int> vec = { 4, 1, 4, 2, 3, 4, 4, 4, 5, 4 };

	removeAllElements(vec, 4);

	print(vec);

	return 0;
}

/*
run:

1 2 3 5

*/

 

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