how to get input in 2d array in c

varType matrix[rows][coloumns];

int disp[2][4] = {
    {10, 11, 12, 13},
    {14, 15, 16, 17}
};

#include <stdio.h>

int main(){

    printf("Enter the number of columns");
    int i; 
    scanf("%d", &i);
    printf("Enter the number of rows");
    int y; 
    scanf("%d", &y);

    int r[i][y];
    int a;
    int b;

        for (a=0; a<i; a++){
            for (b=0; b<y; b++){
    scanf("%d",&r[a][b]);
        }
    }
}