S2184 — Results of integer division should not be assigned to floating point variables

Why is this an issue?

When division is performed on ints, the result will always be an int. You can assign that result to a double, float or decimal with automatic type conversion, but having started as an int, the result will likely not be what you expect. If the result of int division is assigned to a floating-point variable, precision will have been lost before the assignment. Instead, at least one operand should be cast or promoted to the final type before the operation takes place.

Noncompliant code example

static void Main()
{
  decimal dec = 3/2; // Noncompliant
  Method(3/2); // Noncompliant
}

static void Method(float f) { }

Compliant solution

static void Main()
{
  decimal dec = (decimal)3/2;
  Method(3.0F/2);
}

static void Method(float f) { }

Resources

Standards

• CWE - CWE-190 - Integer Overflow or Wraparound
• STIG Viewer - Application Security and Development: V-222612 - The application must not be vulnerable to overflow attacks.