c - 用于对名称列表进行排序的 Perl 脚本，从 C 脚本传递的文件名，然后将排序后的列表传回

Question

我应该能够对文件进行排序: perl -e '打印排序 <>' 数据文件

我想做的是从 C 脚本调用此脚本。 C 脚本将数据文件名传递给 Perl 脚本，然后读取排序后的输出。

我已经准备好代码了:

#include <stdio.h>

FILE *popen(const char *command, const char *mode);
int pclose(FILE *stream);

int main(void){
    FILE *cmd = popen("myperlscript myparams", "r");
    char result[1024];

    while (fgets(result, sizeof(result), cmd) != NULL)
           printf("%s", result);
    pclose(cmd);
    return 0;
}

那么我如何将文件中的姓氏列表:data.txt 从 C 传递到 Perl，并将排序后的列表输出到标准输出？ (它的 Perl 方面)？

Answer 1

只是替换

FILE *cmd = popen("myperlscript myparams", "r");

与

FILE *cmd = popen("perl -e 'print sort <>' data.txt", "r");

我建议你检查一下popen的结果，使用这个:

#include <stdio.h>
#include <stdlib.h>

FILE *popen(const char *command, const char *mode);
int pclose(FILE *stream);

int main(void)
{
    FILE *cmd;
    char result[1024];

    FILE *cmd = popen("perl -e 'print sort <>' data.txt", "r");
    if (cmd == NULL) {
        perror("popen");
        exit(EXIT_FAILURE);
    }
    while (fgets(result, sizeof(result), cmd)) {
        printf("%s", result);
    }
    pclose(cmd);
    return 0;
}

Would it be possible to pass the file name in? (the data.txt) So I can read different file names?

当然，snprintf 和 main 的参数就是为此而生的；)

#include <stdio.h>
#include <stdlib.h>

FILE *popen(const char *command, const char *mode);
int pclose(FILE *stream);

int main(int argc, char *argv[])
{
    char result[1024], str[128];
    FILE *cmd;

    if (argc != 2) {
        fprintf(stderr, "Usage %s filename\n", argv[0]);
        exit(EXIT_FAILURE);
    }
    snprintf(str, sizeof str, "perl -e 'print sort <>' %s", argv[1]);
    cmd = popen(str, "r");
    if (cmd == NULL) {
        perror("popen");
        exit(EXIT_FAILURE);
    }
    while (fgets(result, sizeof result, cmd)) {
        printf("%s", result);
    }
    pclose(cmd);
    return 0;
}

I'll actually be prompting the user to enter a filename once the program starts so passing in argv wouldn't work. (I believe, Very new to C) I could just change this to a perlSort function, and pass arguments that way, yes? To make this easier: ---Start Program ---Prompt user for source data file ---Prompt user for destination data file ---Display Menu: 1 - Sort with C 2 - Sort with Perl 3 - Find word with Perl

所以你想被灌输，好吧，没问题，但下次先自己努力，否则你永远学不会:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

FILE *popen(const char *command, const char *mode);
int pclose(FILE *stream);

int main(void)
{
    char result[1024], tmp[128], *p;
    FILE *cmd;

    printf("Enter a filename: ");
    fgets(tmp, sizeof tmp, stdin);
    p = strchr(tmp, '\n');
    if (p != NULL) *p = '\0';
    snprintf(result, sizeof result, "perl -e 'print sort <>' %s", tmp);
    cmd = popen(result, "r");
    if (cmd == NULL) {
        perror("popen");
        exit(EXIT_FAILURE);
    }
    while (fgets(result, sizeof result, cmd)) {
        printf("%s", result);
    }
    pclose(cmd);
    return 0;
}