How to find the size of an int[]?

arrays, c++

Solution

Try this:

sizeof(list) / sizeof(list[0]);

Because this question is tagged C++, it is always recommended to use `std::vector` in C++ rather than using conventional C-style arrays.

An `array-type` is implicitly converted into a `pointer-type` when you pass it to a function. Have a look at this.

In order to correctly print the sizeof an array inside any function, pass the array by reference to that function (but you need to know the size of that array in advance).

You would do it like so for the general case

template<typename T,int N> 
//template argument deduction
int size(T (&arr1)[N]) //Passing the array by reference 
{
   return sizeof(arr1)/sizeof(arr1[0]); //Correctly returns the size of 'list'
   // or
   return N; //Correctly returns the size too [cool trick ;-)]
}

Problem

I have ``` int list[] = {1, 2, 3}; ``` How to I get the size of `list`? I know that for a char array, we can use `strlen(array)` to find the size, or check with `'\0'` at the end of the array. I tried `sizeof(array) / sizeof(array[0])` as some answers said, but it only works in main? For example: ``` int size(int arr1[]){ return sizeof(arr1) / sizeof(arr1[0]); } int main() { int list[] = {1, 2, 3}; int size1 = sizeof(list) / sizeof(list[0]); // ok int size2 = size(list_1); // no // size1 and size2 are not the same } ``` Why?

Original source

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