matrix 1.1 not work. n/2

#include <iostream>
using namespace std;
void uber(int **a,int n){
    int ch=0;
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            ch+=1;
            a[i][j]=ch;
        }
    }
}

void print(int **a,int n){
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            cout<<a[i][j]<<"\t";
        }
        cout<<endl<<endl;
    }
}

void transpose(int ** a, int n){
    int c=0;
    for(int i=0;i<n;i++){
        for(int j=0;j<n/2;j++){
            c=a[i][j];
            a[i][j]=a[j][i];
            a[j][i]=c;
        }
    }
}

int main()
{
    int b=6;
    int **ptr = new int *[b];
    for ( int i=0; i<b; i++){
       ptr[i] = new int [b];
       for(int j=0;j<b;j++){
           ptr[i][j]=0;
           }
    }
    uber (ptr,b);
    print (ptr,b);
    cout << endl;
    transpose(ptr, b);
    print (ptr,b);
}