using System;
/*
============================================================
Convert a decimal to a long in C#.
This program demonstrates:
• Safe conversion using Convert.ToInt64()
• Direct casting when the value is known to be in range
• A helper function that performs the conversion and
explains what happens internally.
Notes:
• decimal → long conversion requires the value to be within
the range of Int64.
• Convert.ToInt64() rounds to the nearest integer.
• A direct cast (long)decimalValue truncates toward zero.
============================================================
*/
class DecimalToLongProgram
{
// Converts a decimal to a long using the built‑in Convert class.
// This method rounds the decimal to the nearest whole number.
static long ConvertDecimalToLong(decimal value)
{
return Convert.ToInt64(value);
}
// Converts a decimal to a long using a direct cast.
// This method truncates the decimal toward zero.
static long CastDecimalToLong(decimal value)
{
return (long)value;
}
// Prints both conversion styles for comparison.
static void ShowConversions(decimal value)
{
Console.WriteLine("Input decimal: " + value);
long rounded = ConvertDecimalToLong(value);
long truncated = CastDecimalToLong(value);
Console.WriteLine("Rounded (Convert.ToInt64): " + rounded);
Console.WriteLine("Truncated (cast to long): " + truncated);
Console.WriteLine();
}
static void Main()
{
// Example values to demonstrate behavior
ShowConversions(12.7m);
ShowConversions(12.3m);
ShowConversions(-5.8m);
ShowConversions(42m); // already an integer
}
}
/*
run:
Input decimal: 12.7
Rounded (Convert.ToInt64): 13
Truncated (cast to long): 12
Input decimal: 12.3
Rounded (Convert.ToInt64): 12
Truncated (cast to long): 12
Input decimal: -5.8
Rounded (Convert.ToInt64): -6
Truncated (cast to long): -5
Input decimal: 42
Rounded (Convert.ToInt64): 42
Truncated (cast to long): 42
*/
