66: LISTPTR new_rec = NULL; /* Holds address of new rec */
67: LISTPTR tmp_rec = NULL; /* Hold tmp pointer */
68: LISTPTR prev_rec = NULL;
69:
70: /* Allocate memory. */
71: new_rec = (LISTPTR)malloc(sizeof(LIST));
72: if (!new_rec) /* Unable to allocate memory */
73: {
74: printf(“\nUnable to allocate memory!\n”);
75: exit(1);
76: }
77:
78: /* set new link’s data */
79: new_rec->ch = ch;
80: new_rec->next_rec = NULL;
81:
82: if (first == NULL) /* adding first link to list */
83: {
84: first = new_rec;
85: new_rec->next_rec = NULL; /* redundant but safe */
86: }
87: else /* not first record */
88: {
89: /* see if it goes before the first link */
90: if ( new_rec->ch < first->ch)
91: {
92: new_rec->next_rec = first;
93: first = new_rec;
94: }
95: else /* it is being added to the middle or end */
96: {
97: tmp_rec = first->next_rec;
98: prev_rec = first;
99:
100: /* Check to see where link is added. */
101:
102: if ( tmp_rec == NULL )
103: {
104: /* we are adding second record to end */
105: prev_rec->next_rec = new_rec;
106: }
107: else
108: {
109: /* check to see if adding in middle */
110: while (( tmp_rec->next_rec != NULL))
111: {
112: if( new_rec->ch < tmp_rec->ch )
113: {
114: new_rec->next_rec = tmp_rec;428 Day 15LISTING15.13 continued25 448201x-CH15 8/13/02 11:13 AM Page 428