C Programming Code Examples
C > File Operations Code Examples
Compare two Binary Files, Printing the First Byte Position where they Differ
/* Compare two Binary Files, Printing the First Byte Position where they Differ */
#include <stdio.h>
void compare_two_binary_files(FILE *,FILE *);
int main(int argc, char *argv[])
{
FILE *fp1, *fp2;
if (argc < 3)
{
printf("\nInsufficient Arguments: \n");
printf("\nHelp:./executable <filename1> <filename2>\n");
return;
}
else
{
fp1 = fopen(argv[1], "r");
if (fp1 == NULL)
{
printf("\nError in opening file %s", argv[1]);
return;
}
fp2 = fopen(argv[2], "r");
if (fp2 == NULL)
{
printf("\nError in opening file %s", argv[2]);
return;
}
if ((fp1 != NULL) && (fp2 != NULL))
{
compare_two_binary_files(fp1, fp2);
}
}
}
/* compare two binary files character by character */
void compare_two_binary_files(FILE *fp1, FILE *fp2)
{
char ch1, ch2;
int flag = 0;
while (((ch1 = fgetc(fp1)) != EOF) &&((ch2 = fgetc(fp2)) != EOF))
{
/* character by character comparision
if equal then continue by comparing till the end of files */
if (ch1 == ch2)
{
flag = 1;
continue;
}
/* If not equal then returns the byte position */
else
{
fseek(fp1, -1, SEEK_CUR);
flag = 0;
break;
}
}
if (flag == 0)
{
printf("Two files are not equal : byte poistion at which two files differ is %d\n", ftell(fp1)+1);
}
else
{
printf("Two files are Equal\n ", ftell(fp1)+1);
}
}
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Get character from stream. Returns the character currently pointed by the internal file position indicator of the specified stream. The internal file position indicator is then advanced to the next character. If the stream is at the end-of-file when called, the function returns EOF and sets the end-of-file indicator for the stream (feof). If a read error occurs, the function returns EOF and sets the error indicator for the stream (ferror). fgetc and getc are equivalent, except that getc may be implemented as a macro in some libraries.
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