为什么惯于从2参数文件中读取的程序？ [英] Why wont the program read from the 2 argument file?

问题描述

所以，分配是实现使用输入文件子字符串搜索程序，从搜查，被搜索的输入。我创建了以下code：

So the assignment is to implement a substring search program using an input file to be searched from and an input to be searched. I created the following code:

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

int main(int argc,char *argv[])
{
  FILE *fp;
  fp = fopen(argv[1],"r");
  if (fp == NULL)
    {
      printf("Error");
      return 0;
    }
  char* tmpp[100];
  int count = 0;
  char* nexts = argv[2];
  char* tmp = fgets(tmpp,100,fp);
  while(tmp = strstr(tmp,nexts))
    {
      count++;
      tmp++;
    }
  printf("%d\n\n",count);
  fclose(fp);

  return 0;
}    

该程序编译，但是当我去实现它在Ubuntu终端为：

The program compiles but when i go to implement it in the ubuntu terminal as:

echo "aabb" >beta
./a.out beta a
1

为什么心不是使用的第一个参数的程序（的argv [1]）作为测试版和第二个参数（argv [2]）为正确？

Why isnt the program using the first argument (argv[1]) as beta and the second argument (argv[2]) as a correctly?

推荐答案

关闭......但是这是更接近：

Close...but this is closer:

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

int main(int argc, char *argv[])
{
  if (argc != 3)
  {
    fprintf(stderr, "Usage: %s file pattern\n", argv[0]);
    return 1;
  }
  FILE *fp = fopen(argv[1], "r");
  if (fp == NULL)
  {
    fprintf(stderr, "Error: failed to open file %s for reading\n", argv[1]);
    return 1;
  }
  char tmpp[1000];
  int count = 0;
  char* nexts = argv[2];
  while (fgets(tmpp, sizeof(tmpp), fp) != 0)
  {
    char *tmp = tmpp;
    while ((tmp = strstr(tmp, nexts)) != 0)
    {
      count++;
      tmp++;
    }
  }
  printf("%d\n", count);
  fclose(fp);

  return 0;
}

的主要区别是，这种循环读从输入文件多行。你会只输入单行文件上工作。

The main difference is that this loops reading multiple lines from the input file. Yours would only work on files with a single line of input.

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