C++17 range-for with index macro: https://godbolt.org/z/Yd4j8G

foridx.cpp

#include <stdint.h>
#include <stddef.h>
#include <stdio.h>
#include <math.h>

#define for_i(...) \
    if (decltype(sizeof(0)) i_next = 0; true) \
        for (__VA_ARGS__) \
            if (auto i = i_next++; true)

const uint32_t vals[] = {0, 1, 2, 3, 4};

void foridx()
{
    for_i(uint32_t v : vals)
        printf("i: %d\nv: %v", i, v);
}

void rawfor()
{
    uint32_t i = 0;
    for(uint32_t v : vals)
        printf("i: %d\nv: %v", i++, v);
}

int main() {

    return 0;
}