Question

Are parameters evaluated in order when they passed into a method?

For Java it’s always true, for C it isn’t, but what is the answer for C#?

Sample

string.Format("byte1={0} byte2={1} byte3={2}", 
  getNextByte(), 
  getNextByte(), 
  getNextByte());

int pos=0;
byte[] arr=new byte[] {1,2,3,4,5,6};
byte getNextByte()
{
  return arr[pos++];  
}

This sample works, but is it only luck or a rule?

Answer 1

Yes, expressions passed as arguments to methods are always evaluated from left to right.

From the C# 4.0 Language Specification:

7.5.1.2 Run-time evaluation of argument lists

During the run-time processing of a function member invocation (§7.5.4), the expressions or variable references of an argument list are evaluated in order, from left to right, […]