Cleaner way to remove a substring from str in C
Question
I have the following string ID is a sample string remove to /0.10
, I would like to end up with the following: ID/0.10
.
This is what I came up with. However, I'm looking for a cleaner/nicer way of doing this.
#include <stdio.h>
#include <string.h>
int main ()
{
char str[] = "ID is a sample string remove to /0.10";
char *a = strstr(str, "ID");
char *b = strrchr (str, '/');
if (a == NULL)
return 0;
if (b == NULL)
return 0;
int p1 = a-str+2;
int p2 = b-str;
int remL = p2 - p1;
int until = (strlen(str) - p1 - remL) +1;
memmove (str+p1, str+(p1+remL), until);
printf ("%s\n",str);
return 0;
}
Solution
After determining a
and b
you can simplify the memmove
like this:
char str[] = "ID is a sample string remove to /0.10";
char *a = strstr(str, "ID");
char *b = strrchr (str, '/');
if ((a == NULL) || (b == NULL) || (b < a))
return 0;
memmove(a+2, b, strlen(b)+1);
The calculations you do on the string lengths are not really necessary.
OTHER TIPS
#include <stdio.h>
#include <string.h>
int main ()
{
char str[] = "ID is a sample string remove to /0.10";
char *a = strstr(str, "ID");
char *b = strrchr (str, '/');
if (a == NULL || b == NULL)
return 0;
int dist = b - a;
if (dist <= 0) return 0; // aware "/ ID"
a += 2;
while (*a ++ = *b ++);
printf ("%s\n",str);
return 0;
}
Or if you like a very dense version
char str[] = "ID is a sample string remove to /0.10";
char *a = strstr(str, "ID");
char *b = strrchr (str, '/');
if (a == NULL || b < a) return 0; // no need to test b against NULL, implied with <
a ++;
while (*(++ a) = *b ++);
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