Write a program that prints the following 45 pairs of numbers:
11
21
22
31
32
33
41
42
43
44
51

Here is code in C++ to print the following 45 pairs of numbers:

11 21 22 31 32 33 41 42 43 44 51 ...

// include header

#include <bits/stdc++.h>

using namespace std;

//main function

int main() {

//declare variables

int count=0;

int flag=1;

// for loop to print the pattern

for(int i=1;;i++)

{

for(int j=1;j<=i;j++)

  {

// this will print the pairs in vertical manner

     cout<<i<<j<<endl;

//cout<<i<<j<<""; //this will print horizontally

// this will keep count to print only 45 pairs

count++;

// if count is equal to 45 then it will break the inner loop

     if(count==45)

     {

         flag=0;

         break;

     }

}

   // if the flag is eqaul to 45 then it will break the outer loop

   if(flag==0)

     break;

}

return 0;

}

Explanation:

First declare and initialize two variables "count=0" & "flag=1". Here variable

"count" is use to print only 45 pairs and "flag" is used to break the loop when 45 pairs of numbers are printed.In the nested for loop, for every value of i,j will run from 1 to i and print i then j without any space. After every pair, count will incremented by 1. It will check if "count" is greater than 45 or not. If "count" is greater than 45 then it make flag=0 and break the loop. in the outer for loop, if flag is 0 then it break the outer for loop.

Output:

11 21 22 31 32 33 41 42 43 44 51 52 53 54 55 61 62 63 64 65 66 71 72 73 74 75 76 77 81 82 83 84 85 86 87 88 91 92 93 94 95 96 97 98 99