# Functions

## 1. A Simple program without using functions

### Code Listing:

```//
// File name: ~ftp/pub/class/cplusplus/Functions/Absolute1.cpp
// Purpose:   This program find the absolute value of an integer
//	      without using a function
//

#include <iostream>
using namespace std;

int main()
{
int number;
int abs_number;

// Ask for input
cout << "This program finds the absolute value of an integer." << endl;
cout << "Enter an integer (positive or negative): ";
cin >> number;

// Find the absolute value
if(number >= 0)
{
abs_number = number;
}
else
abs_number = -number;

// Print out output
cout << "The absolute value of " << number << " is " << abs_number;
cout << endl;
return 0;
}
```

### Running session:

```mercury[50]% CC -LANG:std Absolute1.cpp -o Absolute1
mercury[51]% Absolute1
This program finds the absolute value of an integer.
Enter an integer (positive or negative): -45
The absolute value of -45 is 45
mercury[52]% Absolute1
This program finds the absolute value of an integer.
Enter an integer (positive or negative): 0
The absolute value of 0 is 0
mercury[53]% Absolute1
This program finds the absolute value of an integer.
Enter an integer (positive or negative): 9
The absolute value of 9 is 9
mercury[54]% ```

## 2. The same program using function

### Code listing:

```//
// File name: ~ftp/pub/class/cplusplus/Functions/Absolute2.cpp
// Purpose:   This program finds the absolute value of an integer
//	      using a function
//

int Abs(int i); // Function prototype
int main()
{
int number;
int abs_number;

cout << "This program finds the absolute value of an integer." << endl;
cout << "Enter an integer (positive or negative): ";
cin >> number;

// Calling the function Abs()
abs_number = Abs(number);
cout << "The absolute value of " << number << " is " << abs_number;
cout << endl;
return 0;
}
// Function definition
int Abs(int i)
{
if( i >= 0)
return i;
else
return -i;
}```

### Running session:

```mercury[56]% CC -LANG:std Absolute2.cpp -o Absolute2
mercury[57]% Absolute2
This program finds the absolute value of an integer.
Enter an integer (positive or negative): -45
The absolute value of -45 is 45
mercury[58]% Absolute2
This program finds the absolute value of an integer.
Enter an integer (positive or negative): 0
The absolute value of 0 is 0
mercury[59]% Absolute2
This program finds the absolute value of an integer.
Enter an integer (positive or negative): -9
The absolute value of -9 is 9
mercury[60]% ```

Last modified: Sunday, 25-Mar-2012 17:49:58 CST
Copyright 2000 Department of Computer Science, University of Regina.
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