Question

Write a C++ program that pick up a random number in text file name number.txt that contains numbers from 6-9.

Cout the number the program picked

Answer 1

/**
* ============================================
*            File Name : read numbers.cpp
* ============================================
* Description: Generates a random index based on total numbers in the
* file . reads till the random index is 0 and prints the number at
* index random index generated.
*/
#include <iostream>
#include <fstream>
#include <sstream>
#include<cstdlib>
#include<ctime>
#define TOTAL_NUMBERS_IN_FILE 4
using namespace std;
int isValidInt(string strNum){
   stringstream ss(strNum);
   int num;
   ss >> num;
   return ss.fail() ? -1 : num;
  
}

void readRandomNumberFromFile(string filename){
   ifstream inp(filename.c_str());
   if(!inp)
   {
       cout<<"\nUnable to find file : "<< filename<<endl;
       return;
   }
   int randInd = rand() % TOTAL_NUMBERS_IN_FILE;
   int num;
   while(randInd >=0 && !inp.eof())
   {
       inp >> num;
       randInd--;
   }
   cout<<"\nRandom Number read from file : "<<num<<endl;
   inp.close();
  
}
int main()
{
   srand(time(0));
   readRandomNumberFromFile("number.txt");
   return 0;
}

number.txt file

6 7 8 9

C:\Windows\SYSTEM32\cmd.exe Random Number read from file : 7 Build <program exited with code: 0 Press any key to continue. Ers in the mber at r3\haMaRa\Deskto pe: unknown 3 > 100% 4:49 PM 5/29/2020

C:\Windows\SYSTEM32\cmd.exe Random Number read from file : 8 Build <program exited with code: 0 Press any key to continue Ers in the mber at r3\haMaRa\Deskto pe: unknown 3 > 100% 4:49 PM 5/29/2020