How do I include "header.h" when compiling in C ? 

 /*-------------------------------------------------------------------------* *--- list.c ---* *--- ---* *--- This file defines struct(s) and functions for counting ---* *--- randomly-generated integers in a linked list. ---* *-------------------------------------------------------------------------*/ #include "header.h" // PURPOSE: To hold elements of a linked list that holds counts of integers. struct ListElement { int item_; int count_; struct ListElement* nextPtr_; }; // PURPOSE: To count the occurrence of 'numNums' numbers generated by // 'getNextNumber()'. Returns linked list with counts. struct ListElement* generateList (int numNums ) { struct ListElement* toReturn = NULL; struct ListElement* prev; struct ListElement* run; int i; for (i = 0; i < numNums; i++) { int nextNum = getNextNumber(); for (prev=NULL, run=toReturn; run!=NULL; prev=run, run=run->nextPtr_) if (run->item_ == nextNum) { run->count_++; break; } if (run == NULL) { struct ListElement* newItemPtr = (struct ListElement*) malloc(sizeof(struct ListElement)); newItemPtr->item_ = nextNum; newItemPtr->count_ = 1; newItemPtr->nextPtr_ = NULL; if (prev == NULL) toReturn = newItemPtr; else prev->nextPtr_ = newItemPtr; } } return(toReturn); } // PURPOSE: To print the list of counts pointed to by 'listPtr'. No return // value. void printList (struct ListElement* listPtr ) { while (listPtr != NULL) { printf("%d: %d time(s) ",listPtr->item_,listPtr->count_); listPtr = listPtr->nextPtr_; } } // PURPOSE: To free the list pointed to by 'listPtr'. No return value. void freeList (struct ListElement* listPtr ) { struct ListElement* next; while (listPtr != NULL) { next = listPtr->nextPtr_; free(listPtr); listPtr = next; } } // PURPOSE: To count the occurrence of 'numNums' numbers generated by // 'getNextNumber()' and put the counts in a linked-list. Prints this // list, and then free()s it. No return value. void countWithList (int numNums ) { struct ListElement* listPtr = generateList(numNums); printList(listPtr); freeList (listPtr); }