use*_*020 83 c command-line-arguments
嗨,我正在尝试编写一个程序,可以逐行,逐字或逐字符地比较两个文件.它必须能够读入命令行选项"-l -w -i或 - "...如果选项是-l,它会逐行比较文件.如果选项是-w,它会逐字比较文件.如果选项是 - 它会自动假定下一个arg是第一个文件名.如果选项是-i,则以不区分大小写的方式对它们进行比较.否则,它默认按字符比较文件
只要-w和-l没有同时输入且没有多于或少于2个文件,输入选项的时间并不重要.
我甚至不知道从哪里开始解析命令行参数.请帮忙 :(
所以这就是我想出的所有代码.我还没有错误检查它,但我想知道我是否以过于复杂的方式写东西？
/*
* Functions to compare files.
*/
int compare_line();
int compare_word();
int compare_char();
int case_insens();
/*
* Program to compare the information in two files and print message saying
* whether or not this was successful.
*/
int main(int argc, char* argv[])
{
/*Loop counter*/
size_t i = 0;
/*Variables for functions*/
int caseIns = 0;
int line = 0;
int word = 0;
/*File pointers*/
FILE *fp1, *fp2;
/*
* Read through command-line arguments for options.
*/
for (i = 1; i < argc; i++) {
printf("argv[%u] = %s\n", i, argv[i]);
if (argv[i][0] == '-') {
if (argv[i][1] == 'i')
{
caseIns = 1;
}
if (argv[i][1] == 'l')
{
line = 1;
}
if (argv[i][1] == 'w')
{
word = 1;
}
if (argv[i][1] == '-')
{
fp1 = argv[i][2];
fp2 = argv[i][3];
}
else
{
printf("Invalid option.");
return 2;
}
} else {
fp1(argv[i]);
fp2(argv[i][1]);
}
}
/*
* Check that files can be opened.
*/
if(((fp1 = fopen(fp1, "rb")) == NULL) || ((fp2 = fopen(fp2, "rb")) == NULL))
{
perror("fopen()");
return 3;
}
else{
if (caseIns == 1)
{
if(line == 1 && word == 1)
{
printf("That is invalid.");
return 2;
}
if(line == 1 && word == 0)
{
if(compare_line(case_insens(fp1, fp2)) == 0)
return 0;
}
if(line == 0 && word == 1)
{
if(compare_word(case_insens(fp1, fp2)) == 0)
return 0;
}
else
{
if(compare_char(case_insens(fp1,fp2)) == 0)
return 0;
}
}
else
{
if(line == 1 && word == 1)
{
printf("That is invalid.");
return 2;
}
if(line == 1 && word == 0)
{
if(compare_line(fp1, fp2) == 0)
return 0;
}
if(line == 0 && word == 1)
{
if(compare_word(fp1, fp2) == 0)
return 0;
}
else
{
if(compare_char(fp1, fp2) == 0)
return 0;
}
}
}
return 1;
if(((fp1 = fclose(fp1)) == NULL) || (((fp2 = fclose(fp2)) == NULL)))
{
perror("fclose()");
return 3;
}
else
{
fp1 = fclose(fp1);
fp2 = fclose(fp2);
}
}
/*
* Function to compare two files line-by-line.
*/
int compare_line(FILE *fp1, FILE *fp2)
{
/*Buffer variables to store the lines in the file*/
char buff1 [LINESIZE];
char buff2 [LINESIZE];
/*Check that neither is the end of file*/
while((!feof(fp1)) && (!feof(fp2)))
{
/*Go through files line by line*/
fgets(buff1, LINESIZE, fp1);
fgets(buff2, LINESIZE, fp2);
}
/*Compare files line by line*/
if(strcmp(buff1, buff2) == 0)
{
printf("Files are equal.\n");
return 0;
}
printf("Files are not equal.\n");
return 1;
}
/*
* Function to compare two files word-by-word.
*/
int compare_word(FILE *fp1, FILE *fp2)
{
/*File pointers*/
FILE *fp1, *fp2;
/*Arrays to store words*/
char fp1words[LINESIZE];
char fp2words[LINESIZE];
if(strtok(fp1, " ") == NULL || strtok(fp2, " ") == NULL)
{
printf("File is empty. Cannot compare.\n");
return 0;
}
else
{
fp1words = strtok(fp1, " ");
fp2words = strtok(fp2, " ");
if(fp1words == fp2words)
{
fputs(fp1words);
fputs(fp2words);
printf("Files are equal.\n");
return 0;
}
}
return 1;
}
/*
* Function to compare two files character by character.
*/
int compare_char(FILE *fp1,FILE *fp2)
{
/*Variables to store the characters from both files*/
int c;
int d;
/*Buffer variables to store chars*/
char buff1 [LINESIZE];
char buff2 [LINESIZE];
while(((c = fgetc(fp1))!= EOF) && (((d = fgetc(fp2))!=EOF)))
{
if(c == d)
{
if((fscanf(fp1, "%c", buff1)) == (fscanf(fp2, "%c", buff2)))
{
printf("Files have equivalent characters.\n");
return 1;
break;
}
}
}
return 0;
}
/*
* Function to compare two files in a case-insensitive manner.
*/
int case_insens(FILE *fp1, FILE *fp2, size_t n)
{
/*Pointers for files.*/
FILE *fp1, *fp2;
/*Variable to go through files.*/
size_t i = 0;
/*Arrays to store file information.*/
char fp1store[LINESIZE];
char fp2store[LINESIZE];
while(!feof(fp1) && !feof(fp2))
{
for(i = 0; i < n; i++)
{
fscanf(fp1, "%s", fp1store);
fscanf(fp2, "%s", fp2store);
fp1store = tolower(fp1store);
fp2store = tolower(fp2store);
return 1;
}
}
return 0;
}
Chr*_*jer 162
据我所知,如何在C中解析命令行参数的三种最流行的方法是:
#include <unistd.h>来自POSIX C库),可以解决简单的参数解析任务.如果你对bash有点熟悉,那么bash内置的getopt是基于GNU libc的Getopt.#include <argp.h>来自GNU C库),它可以解决更复杂的任务并处理类似的事情,例如:
-?,--help用于帮助信息,包括电子邮件地址-V,--version有关版本信息--usage对于使用消息GNU C Library文档有一些很好的Getopt和Argp示例.
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
int main(int argc, char *argv[])
{
bool isCaseInsensitive = false;
int opt;
enum { CHARACTER_MODE, WORD_MODE, LINE_MODE } mode = CHARACTER_MODE;
while ((opt = getopt(argc, argv, "ilw")) != -1) {
switch (opt) {
case 'i': isCaseInsensitive = true; break;
case 'l': mode = LINE_MODE; break;
case 'w': mode = WORD_MODE; break;
default:
fprintf(stderr, "Usage: %s [-ilw] [file...]\n", argv[0]);
exit(EXIT_FAILURE);
}
}
// Now optind (declared extern int by <unistd.h>) is the index of the first non-option argument.
// If it is >= argc, there were no non-option arguments.
// ...
}
#include <argp.h>
#include <stdbool.h>
const char *argp_program_version = "programname programversion";
const char *argp_program_bug_address = "<your@email.address>";
static char doc[] = "Your program description.";
static char args_doc[] = "[FILENAME]...";
static struct argp_option options[] = {
{ "line", 'l', 0, 0, "Compare lines instead of characters."},
{ "word", 'w', 0, 0, "Compare words instead of characters."},
{ "nocase", 'i', 0, 0, "Compare case insensitive instead of case sensitive."},
{ 0 }
};
struct arguments {
enum { CHARACTER_MODE, WORD_MODE, LINE_MODE } mode;
bool isCaseInsensitive;
};
static error_t parse_opt(int key, char *arg, struct argp_state *state) {
struct arguments *arguments = state->input;
switch (key) {
case 'l': arguments->mode = LINE_MODE; break;
case 'w': arguments->mode = WORD_MODE; break;
case 'i': arguments->isCaseInsensitive = true; break;
case ARGP_KEY_ARG: return 0;
default: return ARGP_ERR_UNKNOWN;
}
return 0;
}
static struct argp argp = { options, parse_opt, args_doc, doc, 0, 0, 0 };
int main(int argc, char *argv[])
{
struct arguments arguments;
arguments.mode = CHARACTER_MODE;
arguments.isCaseInsensitive = false;
argp_parse(&argp, argc, argv, 0, 0, &arguments);
// ...
}
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char *argv[])
{
bool isCaseInsensitive = false;
enum { CHARACTER_MODE, WORD_MODE, LINE_MODE } mode = CHARACTER_MODE;
size_t optind;
for (optind = 1; optind < argc && argv[optind][0] == '-'; optind++) {
switch (argv[optind][1]) {
case 'i': isCaseInsensitive = true; break;
case 'l': mode = LINE_MODE; break;
case 'w': mode = WORD_MODE; break;
default:
fprintf(stderr, "Usage: %s [-ilw] [file...]\n", argv[0]);
exit(EXIT_FAILURE);
}
}
// *argv points to the remaining non-option arguments.
// If *argv is NULL, there were no non-option arguments.
// ...
}
免责声明:我是Argp的新手,该示例可能包含错误.
Jon*_*ler 16
使用getopt(),或许getopt_long().
int iflag = 0;
enum { WORD_MODE, LINE_MODE } op_mode = WORD_MODE; // Default set
int opt;
while ((opt = getopt(argc, argv, "ilw") != -1)
{
switch (opt)
{
case 'i':
iflag = 1;
break;
case 'l':
op_mode = LINE_MODE;
break;
case 'w':
op_mode = WORD_MODE;
break;
default:
fprintf(stderr, "Usage: %s [-ilw] [file ...]\n", argv[0]);
exit(EXIT_FAILURE);
}
}
/* Process file names or stdin */
if (optind >= argc)
process(stdin, "(standard input)", op_mode);
else
{
int i;
for (i = optind; i < argc; i++)
{
FILE *fp = fopen(argv[i], "r");
if (fp == 0)
fprintf(stderr, "%s: failed to open %s (%d %s)\n",
argv[0], argv[i], errno, strerror(errno));
else
{
process(fp, argv[i], op_mode);
fclose(fp);
}
}
}
请注意,您需要确定要包含哪些标头(我将其设为4),并且我编写op_mode类型的方式意味着您在函数中遇到问题process()- 您无法访问那里的枚举.最好将枚举移到函数之外; 你甚至可以创建op_mode一个没有外部链接(一种奇特的说法static)的文件范围变量,以避免将其传递给函数.此代码不-作为标准输入的同义词处理,这是读者的另一个练习.请注意,会getopt()自动--为您标记选项的结尾.
我没有在编译器之上运行任何版本的输入; 可能会有错误.
要获得额外的功劳,请写一个(库)函数:
int filter(int argc, char **argv, int idx, int (*function)(FILE *fp, const char *fn));
它封装了getopt()循环后处理文件名选项的逻辑.它应该-作为标准输入处理.请注意,使用它表示op_mode应该是静态文件范围变量.所述filter()函数接受argc,argv,optind和的指针的处理功能.它应该返回0(EXIT_SUCCESS),如果它能够打开所有文件并且函数的所有调用报告为0,否则为1(或EXIT_FAILURE).具有这样的功能简化了编写Unix风格的"过滤器"程序,这些程序读取命令行或标准输入上指定的文件.
我发现Gengetopt非常有用 - 您可以使用简单的配置文件指定所需的选项,并生成一个简单包含并与您的应用程序链接的.c/.h对.生成的代码使用getopt_long,似乎可以处理大多数常见的命令行参数,并且可以节省大量时间.
gengetopt输入文件可能如下所示:
version "0.1"
package "myApp"
purpose "Does something useful."
# Options
option "filename" f "Input filename" string required
option "verbose" v "Increase program verbosity" flag off
option "id" i "Data ID" int required
option "value" r "Data value" multiple(1-) int optional
生成代码很容易并且吐出来cmdline.h并且cmdline.c:
$ gengetopt --input=myApp.cmdline --include-getopt
生成的代码很容易集成:
#include <stdio.h>
#include "cmdline.h"
int main(int argc, char ** argv) {
struct gengetopt_args_info ai;
if (cmdline_parser(argc, argv, &ai) != 0) {
exit(1);
}
printf("ai.filename_arg: %s\n", ai.filename_arg);
printf("ai.verbose_flag: %d\n", ai.verbose_flag);
printf("ai.id_arg: %d\n", ai.id_arg);
int i;
for (i = 0; i < ai.value_given; ++i) {
printf("ai.value_arg[%d]: %d\n", i, ai.value_arg[i]);
}
}
如果您需要进行任何额外的检查(例如确保标志是互斥的),您可以使用gengetopt_args_info结构中存储的数据相当容易地完成此操作.
我很惊讶没有人提出詹姆斯·泰勒（James Theiler）的“选择”方案。
您可以在http://public.lanl.gov/jt/Software/找到opt。
这里有一些讨人喜欢的例子，比起其他方法，它更简单得多：
http://www.decompile.com/not_invented_here/opt/
#include <stdio.h>
int main(int argc, char **argv)
{
size_t i;
size_t filename_i = -1;
for (i = 0; i < argc; i++)
{
char const *option = argv[i];
if (option[0] == '-')
{
printf("I am a flagged option");
switch (option[1])
{
case 'a':
/*someting*/
break;
case 'b':
break;
case '-':
/* "--" -- the next argument will be a file.*/
filename_i = i;
i = i + 1;
break;
default:
printf("flag not recognised %s", option);
break;
}
}
else
{
printf("I am a positional argument");
}
/* At this point, if -- was specified, then filename_i contains the index
into argv that contains the filename. If -- was not specified, then filename_i will be -1*/
}
return 0;
}
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