C how many elements in array

If we don't know the number of elements in the array and when the input is given by the user at the run time. Then we can write the code as. This is not what you want, but it can help.

If you apply sizeof to an element of the array sizeof array[0] , it will return its size in bytes, which in this case is the size of an int , so a total of maybe 4 bytes depending on your implementation. Now you would probably like to have a macro to encapsulate this logic and never have to think again how it should be done:. You need the parentheses enclosing all the macro as in any other complex macro, and also enclosing every variable, just to avoid unexpected bugs related to operators precedence.

Remember that arguments of functions declared as arrays are not really arrays, but pointers to the first element of the array, so this will NOT work on them:. Assuming you have an array with elements 1,3,4. To know its length, you'd need to use the sizeof function as follows:. Actually, there is no proper way to count the elements in a dynamic integer array. However, the sizeof command works properly in Linux, but it does not work properly in Windows.

From a programmer's point of view, it is not recommended to use sizeof to take the number of elements in a dynamic array. We should keep track of the number of elements when making the array. How are we doing? Please help us improve Stack Overflow. Take our short survey. 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. How can I find the number of elements in an array? Ask Question. Asked 9 years, 6 months ago. Active 3 months ago. Viewed k times. Improve this question. Andrew Marshall AndrewP AndrewP 2 2 gold badges 7 7 silver badges 9 9 bronze badges. Take a look at this.

So it's important to keep your array size checking. Add a comment. Active Oldest Votes. Improve this answer. Pavel Zhuravlev Pavel Zhuravlev 2, 1 1 gold badge 17 17 silver badges 16 16 bronze badges. Robert Groves 7, 5 5 gold badges 35 35 silver badges 50 50 bronze badges.

Derek Derek 2 2 silver badges 6 6 bronze badges. You could do this, but it would result in calculating the size every time it does the test in the for loop, so once every iteration. And so it would be doing division every single time thru the loop. It would be more efficient to assign the result of NUM a to an instance variable right above the loop, and use that value in the loop. Gavin no, it wouldn't calculate the size for every iteration. The compiler is smart enough to see that the results of each sizeof as well as the division are constant and determines the result at compile time, which it subsequently compiles into the code as a constant number.

You may have been misled by the looks of the sizeof application, which looks like a function due to the parentheses, but it isn't a function. And that is all. I hope you understood the logic and were able to execute it by yourself. If you have any doubts regarding this, feel free to ask it in the comment section. Thank You. The comment section is only for discussing the above topic. The system is the WordPress default system we are using.

There is minimum length criteria for publishing a comment. If you leave it blank it will not be taken as a valid comment. Thank you very much I found this very helpful keep on Do more and more examples to help people understanding programming Lemme also notice that I found this method amazing thank u again!!!

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