Question

我试图在c中制作SIC汇编程序，制作了一个小型测试程序来搜索＆＃34; START＆＃34;关键字并从汇编代码文件中获取起始地址。然后在第一遍时将它们写在另一个文件中。代码没有用。记住它有什么不对吗？

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

int main(int argc, char *argv[])
{
    FILE *source;
    FILE *intermediate;
    rewind(source);
    char word[10];
    unsigned int address = 0;
    char start[5] = "START";
    source = fopen(argv[1],"r");
    intermediate = fopen(argv[2],"r+");
    while(strcmp(word,start) != 0)
    {
        fscanf(source, "%s", word);
    }
    fscanf(source, "%x", address);
    fprintf(intermediate, "%x", address);
    fprintf(intermediate, "%s", word);

    return(0);
}

这是汇编输入：

  COPY   START  1000
  FIRST  STL    RETADR
  CLOOP  JSUB   RDREC
         LDA    LENGTH
         COMP   ZERO
         JEQ    ENDFIL
         JSUB   WRREC
         J      CLOOP
  ENDFIL LDA    EOF
         STA    BUFFER
         LDA    THREE
         STA    LENGTH
         JSUB   WRREC
         LDL    RETADR
         RSUB
  EOF    BYTE   C'EOF'
  THREE  WORD   3
  ZERO   WORD   0
  RETADR RESW   1
  LENGTH RESW   1
  BUFFER RESB   4096

Answer 1

正如我和其他人在评论中指出的，你有几个错误。

1）使用未初始化的变量（word）

2）在文件未打开时倒带

3）字符串的数组太短（开始）

4）fscanf的错误参数（地址而不是＆amp;地址）

除此之外还有其他问题，如：

1）fscanf中缓冲区溢出的风险

2）缺少对EOF的处理

3）缺少文件关闭

修复上述内容后，代码可能如下所示：

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

int main(int argc, char *argv[])
{
    FILE *source;
    FILE *intermediate;
    char word[10];
    unsigned int address = 0;
    const char start[] = "START";

    source = fopen(argv[1],"r");       // Missing check of argc and successful file open
    intermediate = fopen(argv[2],"w"); // Missing check of argc and successful file open

    do
    {
      if (fscanf(source, "%9s", word) != 1)
      {
        printf("Illegal source file. START not found\n");
        fclose(source);
        fclose(intermediate);
        exit(1);
      }
    } while(strcmp(word, start) != 0);

    fscanf(source, "%x", &address);  // Missing check of return value being 1

    fprintf(intermediate, "%x", address);
    fprintf(intermediate, "%s", word);

    fclose(source);
    fclose(intermediate);

    return(0);
}

最后请注意，代码仍然会遗漏重要的检查，例如提供的参数数量，成功的文件打开以及扫描地址时fscan的返回值。

如何在文件中实现搜索单词然后在另一个文件中写入？

1 个答案: