Handling Arithmetic Overflow

When you are dealing with integer values which are in higher amounts, you might arrive at a situation where the program gives you the wrong output.

Introduction

When you are dealing with the integer values which are in higher amounts, you might arrive at a situation where the program gives you the wrong output.

First, we need to know the ranges of every datatype so that the explanation will be easier.

Datatype	Range
int (32-bit signed)	-2,147,483,648 to 2,147,483,648
long (64-bit signed)	-9,223,372,036,854,775,808 to 9,223,372,036,854,775,807

So, when we use int datatype and if value exceeds the range, the value is taken as -1.

Static assignment of values higher than the range will show compile errors, but if the value is assigned dynamically the compiler doesn’t show any errors.

Whenever arithmetic overflow occurs, the C# compiler is made capable of internally handling the result and sends out an unexpected output.

Example 1 - Code Snippet

int maxValue = 2147483648;

The code will be not compiled as we see a static assignment which is beyond the range. The C# compiler is capable of checking the range and also provides an alternative solution too.

The below compiler error message is thrown.

 

Example 2 - Code Snippet

int maxValue = 2147483647;
maxValue += 1;
Console.WriteLine(maxValue);

Output

-2147483648;

The output is completely unexpected as the value crossed the range of “int”.

Checked Keyword

So, we face a problematic situation now and we need to handle these kinds of situations.

This is called “Arithmetic Overflow”.

C# provides “checked” keyword to handle this issue.

The checked way of the same implementation would be like below.

Code Snippet

int maxValue = 2147483647;
int output = -10;
try {
    output = checked(maxValue + 10);
} catch (OverflowException e) {
    Console.WriteLine("Output = " + output);
}

Output

-10

Conclusion

• Arithmetic Overflow exception was handled successfully.
• Based on your need, you can alter the statement inside catch block to match your requirements.