Hi guys I'm trying to get this program to sort my array in the second option and i think i have the bubble sort written correctly but it doesn't do anything. Any ideas

//This program takes 20 inputs from the user, and gives the choice to show sorted data,

//sort the data into descending order, display the sorted data, and display the address of the first element.

Code:`#include <iostream>`

using namespace std;

#include <iomanip>

#include <algorithm>

int main()

{

int i,num[20],n,j,choice,tmp;

cout<< "Please enter 20 integers";

for (i=0; i<20; i++)

{

cout<<"\nEnter next value:";

cin>>num[i];

}

cout<<"\n1.Display original data.\n";

cout<<"2.Sort the data into descending order\n";

cout<<"3.Display the sorted data (Only if you've already sorted)\n";

cout<<"4.Get the address of the first element of array.\n\n";

cin>>choice;

if (choice==1){

for (i=0; i<20; i++){

cout<<"\n"<<num[i]<<endl;

}

if (choice==2){

for (i=0; i<n-1; i++) {

for (j=0; j<n-1-i; j++)

if (num[j+1] < num[j]) { /* compare the two neighbors */

tmp = num[j]; /* swap a[j] and a[j+1] */

num[j] = num[j+1];

num[j+1] = tmp;

cout<<"Here are your numbers:"<<tmp<<endl;

}

}

}}}