机房建设网站模板,网站建设介绍语,wordpress百度蜘蛛只抓首页,温州文成县高端网站设计您试图从文件中读取的内容并不简单,但可以通过设置一个标志来处理,该标志告诉您是否已经看到a或b,跳过所有空白和:字符,将所有其他字符存储在缓冲区中,根据需要重新分配,然后在第二个“A”或“B”找到了,把那个角色放回FILE*流与ungetc,nul终止并返回缓冲区。听起来很简单——对…您试图从文件中读取的内容并不简单,但可以通过设置一个标志来处理,该标志告诉您是否已经看到a或b,跳过所有空白和:字符,将所有其他字符存储在缓冲区中,根据需要重新分配,然后在第二个“A”或“B”找到了,把那个角色放回FILE*流与ungetc,nul终止并返回缓冲区。听起来很简单——对吧?好吧,差不多了。让我们看看你需要什么readword()功能。首先,因为你分配给buffer在里面Read Word(),不需要通过char **buffer作为参数。你已经声明了readword作为char *readword(...)所以只要通过文件*将指针作为参数,并返回指向NUL终止缓冲器。您可以按自己喜欢的任何方式处理重新分配方案,可以从分配的合理字符数开始,然后将当前大小加倍(或添加一些倍数),或者每次用完时添加一个固定的数量。下面的示例只是从一个32个字符的缓冲区开始,然后在每次需要重新分配时再添加32个字符。(如果数据大小真的未知,我可能会从32个字符开始,然后每次用完都加倍——完全取决于您)。使用isspace()函数位于ctype.h确保正确处理所有空白。最后几个问题只是确保您返回NUL终止缓冲区中的字符串,并确保在以下情况下重新初始化指向每个新内存块中缓冲区结尾的指针realloc被称为。总而言之,你可以做一些类似的事情。在Read Word()函数读取示例文件并输出从文件中读取的组合字符串,#include #include #include #define NCHR 32char *readword (FILE *fp){int c, /* current character */firstline 0; /* flag for a or b found at 1st char */size_t n 0, nchr NCHR; /* chars read, number of chars allocated */char *buffer NULL, *p; /* buffer to fill, pointer to buffer */buffer malloc (nchr); /* allocate initial NCHR */if (!buffer) { /* validate */perror (malloc-buffer);return NULL;}p buffer; /* set pointer to buffer */while ((c fgetc (fp)) ! EOF) { /* read each char */if (isspace (c) || c :) /* skip all whitespace and : */continue;if (c a || c b) { /* begins with a or b */if (firstline) { /* already had a/b line */ungetc (c, fp); /* put the char back */*p 0; /* nul-terminate */return buffer; /* return filled buffer */}firstline 1; /* set firstline flag */continue;}else {if (n nchr - 2) { /* check if realloc needed */void *tmp realloc (buffer, nchr NCHR);if (!tmp) /* validate */exit (EXIT_FAILURE);buffer tmp; /* assign new block to buffer */p buffer n; /* set p at buffer end */nchr NCHR; /* update no. chars allocated */}*p c; /* assign the current char and advance p */n; /* increment your character count */}}*p 0; /* nul-terminate */return buffer;}int main (int argc, char **argv) {char buf[NCHR], *word;int nwords, toggle 0;/* use filename provided as 1st argument (stdin by default) */FILE *fp argc 1 ? fopen (argv[1], r) : stdin;if (!fp) { /* validate file open for reading */perror (file open failed);return 1;}if (!fgets (buf, NCHR, fp)) {fputs (error: read of line 1 failed.\n, stderr);return 1;}if (sscanf (buf, %d, nwords) ! 1) {fputs (error: invalid file format.\n, stderr);return 1;}nwords * 2; /* actual number of words is twice the number of pairs */while (nwords-- (word readword (fp))) {printf (%c: %s\n, toggle ? b : a, word);free (word);if (toggle) {putchar (\n);toggle 0;}elsetoggle 1;}if (fp ! stdin) fclose (fp); /* close file if not stdin */return 0;}(音符:在上面toggle仅仅是一个1或0用于输出的标志a:或b:在适当行的开头添加\n两行之间。)示例使用/输出$ ./bin/read_multiline_pairs dat/pairsbinline.txta: 010101000001010111110100101010000000111100000000000011110000b: 0000011111000001000110101010100111110001a: 0000001111111111110000111111111111000b: 00000001111001010101内存使用/错误检查在动态分配存储空间时,请始终验证内存使用情况,并确保已释放所有分配的内存。$ valgrind ./bin/read_multiline_pairs dat/pairsbinline.txt14257 Memcheck, a memory error detector14257 Copyright (C) 2002-2015, and GNU GPLd, by Julian Seward et al.14257 Using Valgrind-3.12.0 and LibVEX; rerun with -h for copyright info14257 Command: ./bin/read_multiline_pairs dat/pairsbinline.txt14257a: 010101000001010111110100101010000000111100000000000011110000b: 0000011111000001000110101010100111110001a: 0000001111111111110000111111111111000b: 000000011110010101011425714257 HEAP SUMMARY:14257 in use at exit: 0 bytes in 0 blocks14257 total heap usage: 8 allocs, 8 frees, 872 bytes allocated1425714257 All heap blocks were freed -- no leaks are possible1425714257 For counts of detected and suppressed errors, rerun with: -v14257 ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)仔细看一下,如果有问题请告诉我。问题的最大部分是处理每对的所有行的读取和连接。剩下的代码就留给你了。
