在C中解析命令行参数? [英] Parsing command-line arguments in C?
问题描述
我正在尝试编写一个程序,可以在C中逐行,逐字或逐个字符地比较两个文件。它必须能够在命令行选项中读取 -l -w -i或-
...
I'm trying to write a program that can compare two files line by line, word by word, or character by character in C. It has to be able to read in command line options -l -w -i or --
...
- 如果选项为-l,则比较文件行按行。
- 如果选项为-w,则逐字比较文件。
- 如果选项为-它会自动假定下一个arg是第一个文件名。
- 如果选项为-i,则以不区分大小写的方式比较它们。
- 默认情况下比较文件字符
- if the option is -l it compares the files line by line.
- if the option is -w it compares the files word by word.
- if the options is -- it automatically assumes that the next arg is the first filename.
- if the option is -i it compares them in a case insensitive manner.
- defaults to comparing the files character by character.
只要不输入-w和-l,输入选项多少次并不重要同时没有不超过2个文件。
It's not supposed to matter how many time the options are input as long as -w and -l aren't inputted at the same time and there are no more or less than 2 files.
我什至不知道从哪里开始解析命令行参数。
请帮助:(
I don't even know where to begin with parsing the command line arguments. PLEASE HELP :(
所以这是我为所有内容准备的代码。我还没有对它进行错误检查,但是我想知道如果我写的东西太复杂了?
So this is the code that I came up with for everything. I haven't error checked it quite yet, but I was wondering if I'm writing things in an overcomplicated manner?
/*
* 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;
}
推荐答案
据我所知,这三个
- Getopt (
(包括POSIX C库中的#include< unistd.h>
),它可以解决简单参数解析任务。如果您对bash有点熟悉,则bash内置的getopt基于GNU libc中的Getopt。 - Argp (
#include< argp.h>
(来自GNU C库),它可以解决更多的复杂任务并处理诸如:
-
-?
,-help
以获得帮助消息,包括电子邮件地址 -
-V
,-version
获取版本信息 -
-使用情况
获取使用情况消息
- Getopt (
#include <unistd.h>
from the POSIX C Library), which can solve simple argument parsing tasks. If you're a bit familiar with bash, the getopt built-in of bash is based on Getopt from the GNU libc. - Argp (
#include <argp.h>
from the GNU C Library), which can solve more complex tasks and takes care of stuff like, for example:-?
,--help
for help message, including email address-V
,--version
for version information--usage
for usage message
GNU C库文档有一些不错的选择
The GNU C Library documentation has some nice examples for Getopt and Argp.
- http://www.gnu.org/software/libc/manual/html_node/Getopt.html
- http://www.gnu.org/software/libc/manual/html_node/Argp.html
- http://www.gnu.org/software/libc/manual/html_node/Getopt.html
- http://www.gnu.org/software/libc/manual/html_node/Argp.html
#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. // ... }
使用示例 Argp
Example for using Argp
#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); // ... }
自己动手
Example for Doing it Yourself
#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:I是Argp的新手,该示例可能包含错误。
Disclaimer: I am new to Argp, the example might contain errors.
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