For C++, how to return the size of a one-dimensional array or two-dimensional array?
For a one-dimensional array:
define an array by int a[ ]:
#include <iostream>
#include <vector>
using namespace std;
int main()
{
int a[] = {
1,2,3,4,5,6 };
int n = sizeof(a) / sizeof(a[0]); //n为数组长度
cout << n;
return 0;
}
Use vector containers to open up array space
#include <iostream>
#include <vector>
using namespace std;
int main()
{
vector<int> nums;
nums.push_back(1); //赋值操作自由选择，此处只做样例
nums.push_back(2);
nums.push_back(3);
nums.push_back(4);
nums.push_back(5);
nums.push_back(6);
int n = nums.size();
cout << n;
}
For a two-dimensional array
//通过int a[][] 来定义一个二维数组
#include <iostream>
#include <vector>
using namespace std;
int main()
{
int a[2][3] = {
{
1,2,3},{
1,2,3} };
int sum = (sizeof(a) / sizeof(int));
int row = (sizeof(a) / sizeof(int)) / (sizeof(a[0]) / sizeof(int)); //注意加括号
int column = sizeof(a[0]) / sizeof(int); //等价于 int column=sum/row;
cout << sum << endl;
cout << row << endl;
cout << column << endl;
return 0;
}
Define a two-dimensional array through vector and return the ranks of the array
#include <iostream>
#include <vector>
using namespace std;
int main()
{
vector<vector<int> > matrix = {
{
1,2,3},{
4,5,6} };
int row = matrix.size();//行数
int column = matrix[0].size();//列数
cout << row << endl;
cout << column << endl;
return 0;
}