使用不规则数组(ragged array)和agetline()将整个文件读入内存

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 extern char *agetline(FILE *);
 4 FILE *ifp;
 5 
 6 /* assume ifp is open on input file */
 7 
 8 char** lines = NULL;
 9 size_t nalloc = 0;
10 size_t nlines = 0;
11 char *p;
12 
13 while((p = agetline(ifp)) != NULL) {
14     if (nlines >= nalloc) {
15         nalloc += 50;
16 #ifdef SAFEREALLOC
17     lines = realloc(lines, nalloc * sizeof(char*));
18 #else
19     if(lines == NULL)    /* in case pre - ANSI realloc */
20         lines = malloc(lines, nalloc * sizeof(char*));
21     else
22         lines = realloc(lines, nalloc * sizeof(char*));
23 #endif
24         if(lines == NULL) {
25             fprintf(stderr, "out of memeory");
26             exit(1);
27         }
28     }
29     lines[nlines++] = p;
30 }