Robson » Little Red Book » Arithmetic

Chapter 1 - Question 1

Given two integers, output their sum, difference and product.

Solution 1

PHP:

<?
   // two integers, these can be any numbers
   // the numbers are randomly generated to add some variety
   // mt_rand() is a faster version of rand()
   $a = mt_rand(1, 10);
   $b = mt_rand(1, 10);
 
   // show what the numbers are
   echo $a . ' and ' . $b . '<br /> <br />';
   // first, output their sum
   echo 'Sum: ' . ($a + $b) . '<br />';
   // second, output the difference
   // abs() is used in case the second number is greater than the first
   echo 'Difference: ' . abs($a - $b) . '<br />';
   // finally, output the product
   echo 'Product: ' . ($a * $b);
?>    

Which produces:

8 and 7

Sum: 15
Difference: 1
Product: 56

Solution 2

C++:

#include <stdio.h>
#include <stdlib.h>
 
int main ()
{
   int num1, num2;
   
   printf("Enter a number\n>");
   scanf("%d", &num1);
   printf("Enter another number\n>");
   scanf("%d", &num2);
   
   printf("Sum: %d", num1 + num2);
   printf("\nDifference: %d", abs(num1 - num2));
   printf("\nProduct: %d", num1 * num2);
 
   return 0;
}

Solution 3

I've written another C++ solution now that I know a little bit more about the language. This uses more compact code and arguements sent by the user when running the program.

Example usage:

C:\code>arithmetic 9 2
Sum: 11
Difference: 7
Product: 18
C:\code>
#include <stdio.h>
#include <stdlib.h>
 
using namespace std;
 
int main(int argc, char *argv[])
{
   int n1 = atoi(argv[1]), n2 = atoi(argv[2]);
   printf("Sum: %d\nDifference: %d\nProduct: %d", n1 + n2, abs(n1 - n2), n1 * n2);
}

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