﻿ C++ Exercises: Find the Deficient numbers between 1 to 100 - w3resource

# C++ Exercises: Find the Deficient numbers between 1 to 100

## C++ Numbers: Exercise-7 with Solution

Write a program in C++ to find the Deficient numbers (integers) between 1 to 100.

Pictorial Presentation:

Sample Solution:

C++ Code :

``````#include <bits/stdc++.h>
using namespace std;
int getSum(int n)
{
int sum = 0;
for (int i=1; i<=sqrt(n); i++)
{
if (n%i==0)
{
if (n/i == i)
sum = sum + i;
else
{
sum = sum + i;
sum = sum + (n / i);
}
}
}
sum = sum - n;
return sum;
}
bool checkDeficient(int n)
{
return (getSum(n) < n);
}
int main()
{
int n,ctr=0;
cout << "\n\n The Deficient numbers between 1 to 100 are: \n";
cout << " ------------------------------------------------\n";
for(int j=1;j<=100;j++)
{
n=j;
checkDeficient(n)? cout << n<<" ": cout << "";
if(checkDeficient(n))
{ctr++;}
}
cout << endl<<"The Total number of Deficient numbers are: "<<ctr << endl;
}
``````

Sample Output:

``` The Deficient numbers between 1 to 100 are:
------------------------------------------------
1 2 3 4 5 7 8 9 10 11 13 14 15 16 17 19 21 22 23 25 26 27 29 31 32 33 3
4 35 37 38 39 41 43 44 45 46 47 49 50 51 52 53 55 57 58 59 61 62 63 64
65 67 68 69 71 73 74 75 76 77 79 81 82 83 85 86 87 89 91 92 93 94 95 97
98 99
The Total number of Deficient numbers are: 76
```

Flowchart:

C++ Code Editor:

What is the difficulty level of this exercise?

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## C++ Programming: Tips of the Day

How to use the PI constant in C++?

On some (especially older) platforms (see the comments below) you might need to

#define _USE_MATH_DEFINES and then include the necessary header file:
`#include<math.h>`

and the value of pi can be accessed via:

`M_PI`

In math.h (2014) it is defined as:

`# define M_PI           3.14159265358979323846  /* pi */`

but check your math.h for more. An extract from the "old" math.h (in 2009):

```/* Define _USE_MATH_DEFINES before including math.h to expose these macro
* definitions for common math constants.  These are placed under an #ifdef
* since these commonly-defined names are not part of the C/C++ standards.
*/```

However:

1. on newer platforms (at least on my 64 bit Ubuntu 14.04) I do not need to define the _USE_MATH_DEFINES
2. On (recent) Linux platforms there are long double values too provided as a GNU Extension:
`# define M_PIl          3.14159265358979323846`

Ref: https://bit.ly/3G4BgzQ