Why my program ends after I input application number?

Question

Hi can anyone help me with my enrollment project? Program that I wrote stops after user input, and I don't have any idea why this is happening. User must input a 10 digit number or below but after that the program exits. Why my program ends after I input application number less than or equal to 10? please need help

#include <iostream>
#include <string>

using namespace std;

void enter_details()
{
    int x;
    char name[30];
    long application_number;
    char address[50];
    int age, day, month, year;
    string monthName;
    string branch;
    
//student details
    cout << "Enter Name: ";
    cin.get(name,30);
    
    while(1)
    {
        cout << "Enter application number: ";
        cin >> application_number;
        if(application_number<=9999999999)
        break;
        
    }
    cout << "Enter adress: ";
    cin.get(address,50);
    cout << "Enter age: ";
    cin >> age;
    cout << "Enter birthday: mm dd yyyy : ";
    cin >> month >> day >> year;
    cout << "Select Program: "<<endl;
    cout << "1 for Civil Engineering"<<endl;
    cout << "2 for Chemical Engineering"<<endl;
    cout << "3 for Electrical Engineering"<<endl;
    cout << "4 for Electronics Engineering"<<endl;
    cout << "5 for Industrial Engineering"<<endl;
    cout << "6 for Mechanical Engineering"<<endl;
    cin >> x;

// Display numeric month in words
    switch (month)
    {
        case 1: monthName="January";
        break;
        case 2: monthName="February";
        break;
        case 3: monthName="March";
        break;
        case 4: monthName="April";
        break;
        case 5: monthName="May";
        break;
        case 6: monthName="June";
        break;
        case 7: monthName="July";
        break;
        case 8: monthName="August";
        break;
        case 9: monthName="September";
        break;
        case 10: monthName="October";
        break;
        case 11: monthName="November";
        break;
        case 12: monthName="December";
        break;
        default: cout << "Please input a valid date ";
        break;
    }
//Display inputed data
    cout <<endl;
    cout << "Entered Details:"<<endl;
    cout << "Name: "<<name<<endl;
    cout << "Application Number: "<<application_number<<endl;
    cout << "Address: "<<address<<endl;
    cout << "Age: "<<age<<endl;
    cout << monthName<<" "<<day<<","<<year<<endl;
    
//Program selection
    switch (x)
    {
        case 1: branch="Civil Engineering";
        cout << "College of "<<branch<<endl;
        break;
        
        case 2: branch="Chemical Engineering";
        cout << "College of "<<branch<<endl;
        break;
        
        case 3: branch="Electrical Engineering";
        cout << "College of "<<branch<<endl;
        break;
        
        case 4: branch="Electronics Engineering";
        cout << "College of "<<branch<<endl;
        break;
        
        case 5: branch="Industrial Engineering";
        cout << "College of "<<branch<<endl;
        break;
        
        case 6: branch="Mechanical Engineering";
        cout << "College of "<<branch<<endl;
        break;
        
        default: cout << "invalid option"<<endl;
        break;
    } 
}

//call funtions
int main()
    {
        cout << "Enter Student Details"<<endl;
        enter_details();
    }