asked on

replacing strings

What is an easy way to check for the last period in a file path, trucate the extention, and replace it with something else? There may be more than three characters as the extension. The code below just truncates three characters.

For example:
input file = C:\My Projects\Input files\myinputfile1.louis.stuff
output file = C:\My Projects\Input files\myinputfile1.louis.freq_p2

For example:
input file = C:\My Projects\Input files\myinputfile1
output file = C:\My Projects\Input files\myinputfile1.freq_p2

void parse_arguments (int num_args, char *arg_array[])
{
unsigned short BUFFER_LENGTH = 200;

char FileInput[BUFFER_LENGTH] = {'\0'};
char FileOutput[BUFFER_LENGTH] = {'\0'};

strncpy( FileInput, arg_array[1], BUFFER_LENGTH );

strncpy(FileOutput, FileInput, (strlen(FileInput) - 3));

FileOutput[strlen(FileInput) - 3] = '\0';

strcat(FileOutput, "freq_p2");
}

ASKER CERTIFIED SOLUTION

ozo

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niemeyer

It should work even if the file has no extension at all...

char* rename(char* old_name, char* new_ext)
{
static char buffer[200],*end,*dot;
strcpy(buffer,old_name);
end = buffer;
while(*end != 0)
end++;
dot = end;
while(*dot != '.' && dot != buffer)
dot--;
if(dot == buffer) {
dot = end;
*dot = '.';
}
dot++;
while(*new_ext != 0)
*dot++ = *new_ext++;
return buffer;
}

int main()
{
puts(rename("my_file.old","new_ext"));
return 0;
}

lhgarrett

ASKER

> char* rename(char* old_name, char* new_ext)

This looks to be a bit overkill, but thanks.

lhgarrett

ASKER

> strrchr

This works great:

unsigned short length = 0;

if (strrchr(FileInput,'.'))
{
length = strlen(strrchr(FileInput,'.'));
}

strncpy(FileOutput, FileInput, (strlen(FileInput) - length) );

strcat(FileOutput, BinaryExt);

niemeyer

Yes... but my overkill is a lot faster than your code... :-)