How do I pass multiple ints into a vector at once?

问题:

Currently when I have to use vector.push_back() multiple times.

The code I'm currently using is

  std::vector<int> TestVector;
  TestVector.push_back(2);
  TestVector.push_back(5);
  TestVector.push_back(8);
  TestVector.push_back(11);
  TestVector.push_back(14);

Is there a way to only use vector.push_back() once and just pass multiple values into the vector?

回答1:

Try pass array to vector:

int arr[] = {2,5,8,11,14};
std::vector<int> TestVector(arr, arr+5);

You could always call std::vector::assign to assign array to vector, call std::vector::insert to add multiple arrays.

If you use C++11, you can try:

std::vector<int> v{2,5,8,11,14};

Or

 std::vector<int> v = {2,5,8,11,14};

回答2:

You can also use vector::insert.

std::vector<int> v;
int a[5] = {2, 5, 8, 11, 14};

v.insert(v.end(), a, a+5);

Edit:

Of course, in real-world programming you should use:

v.insert(v.end(), a, a+(sizeof(a)/sizeof(a[0])));  // C++03
v.insert(v.end(), std::begin(a), std::end(a));     // C++11

回答3:

You can do it with initializer list:

std::vector<unsigned int> array;

// First argument is an iterator to the element BEFORE which you will insert:
// In this case, you will insert before the end() iterator, which means appending value
// at the end of the vector.
array.insert(array.end(), { 1, 2, 3, 4, 5, 6 });

回答4:

using vector::insert (const_iterator position, initializer_list il); http://www.cplusplus.com/reference/vector/vector/insert/

#include <iostream>
#include <vector>

int main() {
  std::vector<int> vec;
  vec.insert(vec.end(),{1,2,3,4});
  return 0;
}

回答5:

You can also use Boost.Assignment:

const list<int> primes = list_of(2)(3)(5)(7)(11);

vector<int> v; 
v += 1,2,3,4,5,6,7,8,9;

回答6:

These are the three most straight forward methods:

1) Initialize from an initializer list:

std::vector<int> TestVector = {2,5,8,11,14};

2) Assign from an initializer list:

std::vector<int> TestVector;
TestVector.assign( {2,5,8,11,14} ); // overwrites TestVector

3) Insert an initializer list at a given point:

std::vector<int> TestVector;
...
TestVector.insert(end(TestVector), {2,5,8,11,14} ); // preserves previous elements