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Matching first n characters in a line in a file

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# 1  
Old 01-07-2013
Matching first n characters in a line in a file
hi to all,

i am writing a simple file program in C which has to take a string of length n as input and match that input string with first n character of the line in file. if it does not match it has to compare with first n characters of next line. i am finding it difficult to know how exactly to use fseek function to achieve this. please help...

thank you.
# 2  
Old 01-07-2013
I see no point using fseek here. fseek has nothing to do with a file's contents. You will have to read lines one by one, which is what fgets() is for.


Code:
char buf[4096];
FILE *fp=fopen("filename", "r");

while(fgets(buf, 4096, fp) != NULL)
{
        printf("Read line %s\n", buf);
}

fclose(fp);

As for comparing two strings of known lengths, that's what strncmp is for.

Code:
char *string1="abcdefg";
char *string2="abcdqwerty";

if(strncmp(string1, string2, 4) == 0)
{
        printf("The first four characters of these strings are the same\n");
}

# 3  
Old 01-07-2013
thank you.
u made it so simple... thank you vary much..Smilie
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