Editing Infinite loop (section)

===Mathematical errors===
Here is one example of an infinite loop in [[Visual Basic]]:
<syntaxhighlight lang=vbnet>
dim x as integer
do while x < 5
  x = 1
  x = x + 1
loop

</syntaxhighlight>
This creates a situation where <code>x</code> will never be greater than 5, since at the start of the loop code, <code>x</code> is assigned the value of 1 (regardless of any previous value) before it is changed to <code>x</code> + 1. Thus the loop will always result in <code>x</code> = 2 and will never break. This could be fixed by moving the <code>x = 1</code> instruction outside the loop so that its initial value is set only once.

In some languages, programmer confusion about mathematical symbols may lead to an unintentional infinite loop. For example, here is a snippet in [[C (programming language)|C]]:
<syntaxhighlight lang=c>
#include <stdio.h>

int main(void)
{
   int a = 0;
   while (a < 10) {
      printf("%d\n", a);
      if (a = 5)
         printf("a equals 5!\n");
      a++;
   }
   return 0;
}
</syntaxhighlight>

The expected output is the numbers 0 through 9, with an interjected "a equals 5!" between 5 and 6. However, in the line "<code>if (a = 5)</code>" above, the = (assignment) operator was confused with the == (equality test) operator. Instead, this will assign the value of 5 to <code>a</code> at this point in the program. Thus, <code>a</code> will never be able to advance to 10, and this loop cannot terminate.