C++中二维向量的列大小和行大小
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Column size and row size of a 2D vector in C++
提问by jason
I have a vector like this :
我有一个这样的向量：
vector< vector<int> > myVector;
All row and column numbers are same in this vector.
此向量中的所有行号和列号都相同。
I want to find row count and column count of this vector.
我想找到这个向量的行数和列数。
For row count I come up with :
对于行数，我想出了：
myVector[0].size();
For column count, I can't come up with anything. Can you tell me if my row count is correct and can you tell me how I can get column count? Thanks.
对于列数，我想不出什么。你能告诉我我的行数是否正确，你能告诉我如何获得列数吗？谢谢。
采纳答案by Kilppari
You have a vector of integer vectors
myVector[0].size()returns you the amount of elements in the first int vector in the 2d vector.
您有一个整数向量向量
myVector[0].size()返回二维向量中第一个 int 向量中的元素数量。
The structure of such vector looks like this:
此类向量的结构如下所示：
myVector[
Vector[0, 4, 2, 5],
Vector[1, 4, 2]
];
When you call for myVector[1].size() it would return 3 and [0] would return 4.
当您调用 myVector[1].size() 时，它将返回 3，而 [0] 将返回 4。
For the amount of rows (int vectors) in the 2d vector, you can just use myVector.size()
对于二维向量中的行数（整数向量），您可以使用 myVector.size()
You can run this to see it in actions
您可以运行它以在操作中查看它
#include <iostream>
#include <vector>
int main(){
std::vector<std::vector<int>>MyVector;
std::vector<int>temp;
temp.push_back(1);
temp.push_back(2);
temp.push_back(3);
MyVector.push_back(temp);
std::cout << "Rows in the 2d vector: " << MyVector.size() <<
std::endl << "Collumns in the 1st row: " << MyVector[0].size() <<
std::endl;
system("pause");
return 0;
}
回答by Manjunath Jakaraddi
for(int i=0;i<v.size();i++){
for(int j=0;j<v[i].size();j++){
cout<<v[i][j]<<" ";
}
cout<<endl;
}
Here v is a two dimensional vector of varying size in terms of column size. Use v.size() as it gives the total number of rows and v[i].size() gives you the total number of colums in ith row. The following code can be used to iterate through varying two dimensional vector.
这里 v 是一个二维向量，在列大小方面具有不同的大小。使用 v.size() 因为它给出总行数，而 v[i].size() 给出第 i 行的总列数。以下代码可用于迭代不同的二维向量。
回答by Nikhil Arora
To find the number of rows in a 2D vector , you can simply use vector_name.size(). this will return the size of vector. to find number of columns in Ith row use vector_name[i].size()
要查找 2D vector 中的行数，您可以简单地使用 vector_name.size()。这将返回向量的大小。要查找第 I 行中的列数，请使用 vector_name[i].size()
回答by Shivam Dhanauria
vector_name.size()gives you the numbers of column in a 2D vector and vector_name[0].size()gives you the numbers of rows in a 2D vector in C++.
vector_name.size()为您提供二维向量中的列数，而vector_name[0].size()为您提供 C++ 中二维向量中的行数。
