Does C have a “foreach” loop construct?

Question

Almost all languages have a foreach loop or something similar. Does C have one? Can you post some example code?

Answer 1

C doesn't have a foreach, but macros are frequently used to emulate that:

#define for_each_item(item, list) \
    for(T * item = list->head; item != NULL; item = item->next)

And can be used like

for_each_item(i, processes) {
    i->wakeup();
}

Iteration over an array is also possible:

#define foreach(item, array) \
    for(int keep = 1, \
            count = 0,\
            size = sizeof (array) / sizeof *(array); \
        keep && count != size; \
        keep = !keep, count++) \
      for(item = (array) + count; keep; keep = !keep)

And can be used like

int values[] = { 1, 2, 3 };
foreach(int *v, values) {
    printf("value: %d\n", *v);
}

Edit: In case you are also interested in C++ solutions, C++ has a native for-each syntax called "range based for"