int m, n; cin>>m>>n; double ** T = new double*[n]; for(int i=0; i<m; i++){ T[i] = new double[m]; }

Question

how to declare a allocatable matrix!

Answer 1

int main() {
int m,n;
cin>>m>>n;
int **a = new int*[m];
for(int i=0;i<m;i++){
a[i] = new int[n];
}
}
you have done it the correct way.