Arrays in J programming Language
c++, j
Solution
The literal (but still pretty idiomatic) way to write this in J would be as follows.
m =: 100 $ 0 NB. This means create a 1d array consisting of 100 zeros.
j =: 5
y =: 10
With that initialization out of the way, now we're ready for the meat of the answer, which consists of two different usages of the `}` adverb ("Item Amend" and "Amend").
m =: y j } m
Putting two arguments to the left of the `}` causes J to replace the `j`th element of the right hand argument `m` with the value `y`. NOTE: we had to assign the result back in to `m` because the result of `y j } m` was simply to compute a new array which incorporated the change that you requested using the `}` verb.
y =: j } m
Putting only one argument to the left of the `}` causes J to excerpt the `j`th element of `m` and return it. In this case, we set y to the result.
Problem
How does one do array accesses in the J programming language? For example, using C++ as my pseudocode language: ``` int M [100]; // declare an array called M int j = 5; //index into the array int y = 10; //value to store or load from the array M[j] = y; // store y into the array y = M[j]; // load y from the array ``` What would these sorts of array accesses look like in idiomatic J?