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Arrays decay to pointers in function calls. It's not possible to compute the size of an array which is only represented as a pointer in any way, including using sizeof.

You must add an explicit argument:

void show(int *data, size_t count); 

In the call, you can use sizeof to compute the number of elements, for actual arrays:

int arr[] = { 1,2,3,4,5 }; show(arr, sizeof arr / sizeof *arr); 

Note that sizeof gives you the size in units of char, which is why the division by what is essentially sizeof (int) is needed, or you'd get a way too high value.

Arrays decay to pointers in function calls. It's not possible to compute the size of an array which is only represented as a pointer in any way, including using sizeof.

You must add an explicit argument:

void show(int *data, size_t count); 

In the call, you can use sizeof to compute the number of elements, for actual arrays:

int arr[] = { 1,2,3,4,5 }; show(arr, sizeof arr / sizeof *arr); 

Note that sizeof gives you the size in units of char, which is why the division by what is essentially sizeof (int) is needed, or you'd get a way too high value.

Also note, as a point of interest and cleanliness, that sizeof is not a function. The parentheses are only needed when the argument is a type name, since the argument then is a cast-like expression (e.g. sizeof (int)). You can often get away without naming actual types, by doing sizeof on data instead.

Arrays decay to pointers in function calls. It's not possible to compute the size of an array which is only represented as a pointer in any way, including using sizeof.

You must add an explicit argument:

void show(int *data, size_t count); 

In the call, you can use sizeof to compute the number of elements, for actual arrays:

int arr[] = { 1,2,3,4,5 }; show(data, sizeof arr / sizeof *arr); 

Note that sizeof gives you the size in units of char, which is why the division by what is essentially sizeof (int) is needed, or you'd get a way too high value.

Arrays decay to pointers in function calls. It's not possible to compute the size of an array which is only represented as a pointer in any way, including using sizeof.

You must add an explicit argument:

void show(int *data, size_t count); 

In the call, you can use sizeof to compute the number of elements, for actual arrays:

int arr[] = { 1,2,3,4,5 }; show(arr, sizeof arr / sizeof *arr); 

Note that sizeof gives you the size in units of char, which is why the division by what is essentially sizeof (int) is needed, or you'd get a way too high value.

Sigh.

Arrays decay to pointers in function calls. It's not possible to compute the size of an array which is only represented as a pointer in any way, including using sizeof.

You must add an explicit argument:

void show(int *data, size_t count); 

In the call, you can use sizeof to compute the number of elements, for actual arrays:

int arr[] = { 1,2,3,4,5 }; show(data, sizeof arr / sizeof *arr); 

Note that sizeof gives you the size in units of char, which is why the division by what is essentially sizeof (int) is needed, or you'd get a way too high value.

Arrays decay to pointers in function calls. It's not possible to compute the size of an array which is only represented as a pointer in any way, including using sizeof.

You must add an explicit argument:

void show(int *data, size_t count); 

In the call, you can use sizeof to compute the number of elements, for actual arrays:

int arr[] = { 1,2,3,4,5 }; show(data, sizeof arr / sizeof *arr); 

Note that sizeof gives you the size in units of char, which is why the division by what is essentially sizeof (int) is needed, or you'd get a way too high value.