How to return vector size with sizeof()?

Question

This is the code I’m using, but the return of the tamVet function is not the vector size, but the pointer size on itself.

#include <stdio.h>

int tamVet(int *vet){
    int tam;
    tam = sizeof(vet) / sizeof(vet[0]);
    return tam; //Está retornando 1 invés de 10, o número de elementos de vetor[10]
}

int main(){
    int vetor[10];
    printf("%i", tamVetor(vetor));
    return 0;
}

Answer 1

In C, as soon as you pass an array to a function the array "decays" to a pointer to its first element. The length of the vector is forgotten and the only way to pass it to the function is by using a separate argument. For example, the main gets an argument argc beyond the vector argv.

In your case, if the only thing you want to do is create something to have to type less I think you can solve using macros instead of functions.

#define TAMVET(vet) (sizeof(vet)/sizeof((vet)[0]))