c - 两个文件在C程序中分别输出一行

Question

我正在尝试创建一个 main 函数，该函数采用命令行参数，允许该程序打开两个文件(命令行上提供的路径)并将这两个文件一次一行地组合成一个输出。提供的第一个文件是文本行。删除所有尾随空格、制表符和新行。第二个文件是一个数字列表，打印到输出时必须为每个数字加一个。此外，两列应以制表符分隔。

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

const int MAXLEN = 4096;
const int MAXLINES = 10;

int main(int argc, char *argv[]) {

  char buffer[MAXLEN];
  char buffer2[MAXLEN];
  FILE *fp = fopen(argv[1], "r");
  FILE *fp2 = fopen(argv[2], "r");

  if (!fp || !fp2) {
    perror ("Not Found");
    exit (EXIT_FAILURE);
  }

  int n = 0;
  while((n < MAXLINES) && (fgets (buffer, sizeof (buffer), fp)) && (fgets(buffer2, sizeof (buffer2), fp2))) {
    printf("%s\t%s", buffer, buffer2);
    n++;    
    }
  }

  fclose(fp);
  fclose(fp2);

  return 0;
}

例如对于输入和输出:

./c2 test/c2-testa test/c2-testb

  Test A  11
  Test B  51
  Test C  91
  Test D  26
  Test E  17
  Test F  76

这是我在 gcc 命令后收到的:

c2:
c2.c:53:7: warning: data definition has no type or storage class
       fclose(fp);
       ^~~~~~
c2.c:53:7: warning: type defaults to ‘int’ in declaration of ‘fclose’ [-Wimplicit-int]
c2.c:53:7: warning: parameter names (without types) in function declaration
c2.c:54:7: warning: data definition has no type or storage class
       fclose(fc2);
       ^~~~~~
c2.c:54:7: warning: type defaults to ‘int’ in declaration of ‘fclose’ [-Wimplicit-int]
c2.c:54:7: warning: parameter names (without types) in function declaration
c2.c:56:7: error: expected identifier or ‘(’ before ‘return’
       return 0;
       ^~~~~~
c2.c:58:7: error: expected identifier or ‘(’ before ‘}’ token
       }
       ^
make: *** [Makefile:31: c2.o] Error 1

Answer 1

您所做的是为第一个文件的每一行打印第二个文件的所有行(嵌套循环)。你的循环应该是这样的:

  int n = 0;
  while((n < MAXLINES) && (fgets (buffer, sizeof (buffer), fp)) && (fgets(buffer2, sizeof (buffer2), fp2))) {
    printf("%s\t%s", buffer, buffer2);
    n++;    
  }

请注意，这不会处理“删除尾随空格”。您可能需要为此做一些额外的处理。

此外，打开文件后的条件应该是 if(!fp || !fp2) 以确保两个文件都可以打开!!