为向量的向量赋值

Question

i have created a vector of vectors or 2d arrays of size nxn . i want to assign some n-2 values to each position to this vector, ie for example grid[1][2]=3 and the values 3 should not be same for other position in a vector only grid[1][2] should have the value 3. could anybody help me with the code, also can we use srand function to do this? Thanks

Answer 1

Assuming that you don't have any limitation on the random number generated, here is an example that populates and then print 2D vector array:

int n = 3;
std::vector<int> usedNumbers(n*n);
std::vector<std::vector<int>> vec(n);
for (int i = 0; i < n; i++)
{
    vec[i].resize(n);
    for (int j = 0; j < n; j++)
    {
        int randNum;
        while (std::find(usedNumbers.begin(), usedNumbers.end(), randNum = rand()) != usedNumbers.end()){}
        usedNumbers.push_back(randNum);
        vec[i][j] = randNum;
    }
}
// print the 2 dimentional vector
for (int i = 0; i < n; i++)
for (int j = 0; j < n; j++)
    std::cout << "i:" << i << " j:" << j << " vec: " << vec[i][j] << std::endl;

This reference code also assumes that the random number should be unique in the entire 2D array.

you can play with the rand() function to reflect the maximum number you want (for example, random number x should be in the range of 0 < x < n), but a better option would be to use random .