CODEWITHSUNDEEP
arraysd
user15002651
user15002651

Reputation:

Check If Index Exists in Array D

I apologize in advance if anything isn't clear enough.

While attempting to check if an index value exists of an array in D, I encountered an unexpected RangeError. I'm attempting to make an array check function, and I wouldn't know how to check for a value in an array in D. In C, I would use arr[index].

Execution Error:

[email protected](6): Range violation
----------------
??:? _d_arrayboundsp [0x100f855d9]
??:? int checkArray(immutable(char)[][]) [0x100f6715e]
??:? _Dmain [0x100f7832e]

Code:

import std.stdio;
import std.stdc.stdlib;
import core.sys.posix.unistd;

int checkArray(string[] arr) {
    if (!arr[1]) {
        return 0;
    } else {
        return 1;
    }
}

void main() {
    string base = "test";
    string[] cut = base.split(" ");
    checkArray(cut);
}

I currently use a Mac, and used DMD to compile the source.

Should I try some other checker, other than arr[index]?

Upvotes: 0

Views: 118

Answers (1)

CentralCee
CentralCee

Reputation: 40

Firstly, never ever check if an index is within an array by dereferencing it.

bool check(int[] arr, size_t index)
{
    return index < arr.length;
}

unittest {
    assert(!check([], 0));
    assert(!check([1], 1));
    assert(check([1, 2], 1));
    auto testArray = new int[1024];
    //testArray[testArray.length] = 1; // this throws, so check should return false
    assert(!check(testArray, testArray.length));
}

enjoy

Upvotes: 1

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