Question

Write a C++ program that creates a file called Readings.txt. Inside the file, your program must create
a list. The list is composed of integer double pairs. There is one pair per line. The integers are in
sequence (0, 1, 2, 3, ...) beginning with zero and ending with some random value between 512 and
1024. The doubles should be random values between 50.000 and 90.000. The doubles only have 3
decimal places. The file should look like this (of course your doubles will be random, and there will
be more than 5 readings):

0, 56.347
1, 78.231
2, 89.999
3, 68.002
4, 55.128

Answer 1

#include <iostream>
using std::cerr;
using std::endl;
#include <fstream>
using std::ofstream;
#include <cstdlib>
#include<bits/stdc++.h>

int main()
{
ofstream op;
int i;
   op.open("Readings.txt");
if( !op ) {
cerr << "file not found" << endl;
exit(1);
}
   int nums=512+ ( std::rand() % ( 1025 - 512 + 1 ));
   for (i=0; i<nums; ++i){
   float sub=90.0 + (rand() /( RAND_MAX / (50.0-90.0) ) );
op <<i<<"\t"<<floor(sub*1000)/1000<<endl;
   }
op.close();
return 0;
}

#output: