PreIncrement

PreIncrement[a] adds 1 to a and returns the new value.

Attributes[PreIncrement] := {HoldFirst, Protected, ReadProtected}

Simple examples

In[1]:= toModify = 3
Out[1]= 3

In[2]:= PreIncrement[toModify]
Out[2]= 4

In[3]:= toModify
Out[3]= 4