memset function in C++ not working properly

Question

I tried initializing a dynamically allocated (2D?) array as all is (i>0) using memset. But then , when I am printing out the values of the array, it is printing some garbage. Following is my code snippet:

int main() {
    int T=1, R=3, C=3;
    int **grid = new int*[R], *temp = new int[R*C];
    for (int i=0; i<R; i++)
        grid[i] = (temp+(C*i));
    for (int t=1; t<=T; t++){
        memset(temp,1,sizeof(int)*R*C);
        cout << t << ":\n";
        for (int i=0; i<R; i++){
            for (int j=0; j<C; j++)
                cout << grid[i][j] << " ";
            cout << endl;
        }
    }
    delete [] grid;
    delete [] temp;
    return 0;
}

And the following is the output:

1:
16843009 16843009 16843009
16843009 16843009 16843009
16843009 16843009 16843009

But, if I try to initialize it with 0, it works fine and displays:

1:
0 0 0
0 0 0
0 0 0

I am relatively new to learning C++. What is going wrong with the code?

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Answer 1

memset writes to every byte not to every int in the array.

The value 16843009 in hex is 0x01010101 an int with 4 bytes each of them set to 1.

memset will operate on bytes, there is no way to make it operate on integers.