Question

Write a C++ program which repeatedly asks the user to enter their contact numbers. Create a string
variable named “Phone_No” and take the input in the following pattern: “[phone]” where the
first three characters represent country code (e.g., +92 as shown in the example pattern), next two
characters (e.g., 42 according the shown example number) represent the city code, while next 7
characters represent the actual number.
Your task is to display appropriate messages for the numbers belonging to three cities: Islamabad (having city
code 51), Lahore (city code 42), and Karachi (city code: 21). Any number having different country code or city
code must be reported as “Un-known number“. Please also ensure that the user must enter the number
according to the shown pattern only and the size of the input string must be 12 characters.

Answer 1

#include <iostream>
#include <string.h>
using namespace std;
int main () {
  string Phone_No;
  while (true) {
    cout << "Enter your contact number: " << endl;
    cin >> Phone_No;
    if (Phone_No[0] == '+' && Phone_No[1] == '5' && Phone_No[2] == '1') {
      cout << "The number is belon to Islamobod." << endl;
    }
    else if (Phone_No[0] == '+' && Phone_No[1] == '4' && Phone_No[2] == '2') {
      cout << "The number is belon to Lahore." << endl;
    }
    else if (Phone_No[0] == '+' && Phone_No[1] == '2' && Phone_No[2] == '1') {
      cout << "The number is belon to Karachi." << endl;
    }
    else {
      cout << "Un-known number" << endl;
    }
  }
  return 0;

}