该程序应查看 的每一行，file1然后查看 . 中是否存在完全相同的行file2。如果是，则将该行复制到一个名为 output 的新文件中。
说，以下是文件的内容（可能是句子，但为简单起见，我放了数字。）-
file1 file2
1 2
2 4
3 15
4 6
5 11
6 8
7
8
9
然后output文件应该看起来像 -
(Expected) output
2
4
6
8
在 shell 内部，我可以看到 printfoutput按预期打印，但是 fprintf 颠倒了顺序，我不明白为什么？打印到输出文件的输出是 -
output
8
6
4
2
这是代码 -
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main()
{
FILE *file1, *file2, *output;
int c;
/*Creating buffers where data will be stored for comparison*/
char buffer1[999], buffer2[999];
/*Settig the buffer characters array to 0*/
memset(buffer1, 0, sizeof(buffer1));
memset(buffer2, 0, sizeof(buffer2));
/*Open output file in "w" so that it clears the file*/
output = fopen("output", "w");
/*Open file1 and then save the line inside buffer1 (within while loop)*/
file1 = fopen("file1", "r");
/*Read each character in file until End Of Line*/
while((c = getc(file1)) != EOF)
{
int i = 0;
/*Save each new line of file1 in buffer1 for comparison*/
while(c != '\n')
{
buffer1[i++] = c;
c = getc(file1);
}
/*Open file2 and then save it's line in buffer2 (withing while loop)*/
file2 = fopen("file2", "r");
int ch;
while((ch = getc(file2)) != EOF)
{
i = 0;
while(ch != '\n')
{
buffer2[i++] = ch;
ch = getc(file2);
}
/*Compare lines of file1 against each line of file2*/
if(strcmp(buffer1,buffer2) == 0)
{
/*Save similar lines in a file named output*/
output = fopen("output", "a");
fprintf(output,"%s\n", buffer2);
printf("%s\n", buffer2);
break;
}
/*Reset the buffer*/
memset(buffer2, 0, sizeof(buffer2));
}
memset(buffer1, 0, sizeof(buffer1));
}
/*Close the output file if there were any comparison made i.e. if file was opened*/
if(output != NULL)
{
fclose(output);
}
/*Close other files*/
fclose(file1);
fclose(file2);
return 0;
}