Euler is an important programming language, because it was one of the first programming languages which had pointers (in 1965).

Moreover, it was the first programming language where the implicit value of a pointer was the address contained by it and an explicit operator was used to access the pointed object (in the previous language with pointers, CPL, they behaved like the references of C++, i.e. their implicit value was the pointed object).

Unlike in C, where due to a design error the "*" indirection operator is a prefix operator, in Euler the indirection operator (which was a middle dot) was rightly a postfix operator (this was later inherited by Pascal).

Of course, Euler also had the "address of" operator ("@" in Euler, as a prefix operator), which is needed to assign values to pointers.