Step 4 of 6

const-correct interfaces

In a header, a function's signature is a contract. Mark every pointer parameter the function only reads as const:

size_t count_alive(const Player *team, size_t n);   /* reads only */
void heal_all(Player *team, size_t n, int amount);  /* modifies */

Callers can then pass const data safely, and readers know at a glance which functions have side effects. Adding const later is painful because it ripples through every caller, so get it right from the start.

Your turn: fix the three signatures. The read-only ones need const; heal_all really does modify the team, so it must stay non-const.

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