If you declare the pointer with an index of one, programs would normally add that value of one to the pointer to access the content which is not what you want, of course. Try to access a pixel screen using X,Y coordinates on a 1-based matrix. The formula is utterly complex. Why is complex? Because you end up converting the X,Y coords into one number, the offset. Why you need to convert X,Y to an offset? Because that's how memory is organized inside computers, as a continuous stream of memory cells arrays.
How computers deals with array cells? Using offsets displacements from the first cell, a zero-based indexing model. So at some point in the code you need or the compiler needs to convert the 1-base formula to a 0-based formula because that's how computers deal with memory.
In array, the index tells the distance from the starting element. So, the first element is at 0 distance from the starting element. So, that's why array start from 0. Array name is a constant pointer pointing to the base address. Since int range is to ,the compiler thinks that to -1 are negative numbers and 0 to are positive numbers. So array index always starts with zero. Stack Overflow for Teams — Collaborate and share knowledge with a private group.
Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Why does the indexing start with zero in 'C'? Ask Question. Asked 10 years, 2 months ago. Active 1 year, 4 months ago. Viewed k times. Why does the indexing in an array start with zero in C and not with 1? Improve this question. Nitish Pareek Nitish Pareek 2, 3 3 gold badges 17 17 silver badges 18 18 bronze badges. It's all about Pointers! A pointer array is a memory direction and index is an offset of that memory direction, so the first element of the pointer array is the one who offset is equal to 0.
Americans count the floors storeys of a building from one on the ground floor; the British count from zero ground floor , moving up to the first floor, then the second floor, etc. Show 3 more comments. Active Oldest Votes. Improve this answer. Keith Thompson k 39 39 gold badges silver badges bronze badges.
Massimiliano Peluso Massimiliano Peluso The name of an array is the name of the array; contrary to the common misconception, arrays are not pointers in any sense. An array expression such as the name of an array object is usually, but not always , converted to a pointer to the first element.
Example: sizeof arr yields the size of the array object, not the size of a pointer. While you obviously didn't reacted to KeithThompson's comment, I would like to you use a more offense course: " In C, the name of an array is essentially a pointer, a reference to a memory location " - No, it is not. At least not in a generic point of view. While your answer perfect answers the question in a manner how 0 as index start is important, the first sentence is plain incorrect.
An array does not always decay to a pointer to its first element. Quote from the C standard, C18 , 6. If the array object has register storage class, the behavior is undefined.
Also this decay is happen in a more "implicit" or "formally" way than suggested here; there is no decay to a pointer object in memory involved. This is object of this question: Is the array to pointer decay changed to a pointer object? Add a comment. This question was posted over a year ago, but here goes About the above reasons While Dijkstra's article previously referenced in a now-deleted answer makes sense from a mathematical perspective, it isn't as relevant when it comes to programming.
This can be tested quite easily. Conclusion The decision to start count at 0 , has since permeated all digital systems , including the software running on them, because it makes it simpler for the code to translate to what the underlying system can interpret.
Quoting from the paper:. What if they had just removed the bit Are you actually suggesting modification of basic arithmetic to make it fit in?
Why does the indexing of Array start with Zero in C? By Vineet Choudhary. Primary C C Programming Interview. Prev article. Next article. Share Tweet Send. No results found. You've successfully subscribed to Developer Insider. Next, complete checkout for full access to Developer Insider. Welcome back! Check if every index i has an index j such that sum of elements in both directions are equal. Number of permutations such that sum of elements at odd index and even index are equal. Count of contiguous subarrays possible for every index by including the element at that index.
Check if it is possible to reach to the index with value K when start index is given. Article Contributed By :. Harish Kumar Easy Normal Medium Hard Expert. Writing code in comment? Please use ide. Load Comments. What's New. Most popular in Arrays. Most visited in C Language.
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