Thread: C ...String replacement... command line arguments

Hello,
I am writing a program that uses command line argument for string replacement:
a sample run of the program should be like:
programname.out I like studying like hate
outputs:
I hate studying.

here is the code I wrote :
It is giving Segmentation fault error.
could you please modify the code for me so it works.
thanks

Code:

#include <stdio.h>
#include <string.h>
int main (int argc,char *argv[]) {
char *p, *find, *replace;

p = argv[1];
find =argv[2];
replace =argv[3];
size_t len=strlen(p);
size_t s_len=strlen(find);
size_t r_len=strlen(replace);
char *current=p;
while ((current = strstr(p,find))) {
memmove(current + r_len , current + s_len,len - (current - p) - s_len + 1);
memcpy(current, replace, r_len);
}
++p;
printf("%s\n",argv[1]);
}

Additional Details
This is another version that does not use command line arguments...
It works fine :

Code:

#include <stdio.h>
#include <string.h>

int main () {

char str[1000];
char search[10];
char replace[10];
gets(str);
gets(search);
gets(replace);
size_t len = strlen(str);
size_t s_len = strlen(search);
size_t r_len = strlen(replace);
char *current = str;
while (current = strstr(current, search)) /*assignment*/ {
memmove(current + r_len , current + s_len,len - (current - str) - s_len + 1);
memcpy(current, replace, r_len);
++current;
}
printf("%s",str);
}

Can't figure out what's needed from your post so provide more explanation.

Spammed here as well

Originally Posted by rags_to_riches

Spammed here as well

well I thought my chances of getting answers would be more...

Well then how about providing a clear-cut explanation.

It works fine here, IF you give it three command line arguments. If you don't....

Originally Posted by andrew1400

well I thought my chances of getting answers would be more...

That is rude, and takes for granted the time spent by others here to help you when you're already getting help somewhere else. Which is why I try to let people know when I see this happening; because I am trying to be considerate of other people's time and effort.

Originally Posted by rags_to_riches

That is rude, and takes for granted the time spent by others here to help you when you're already getting help somewhere else. Which is why I try to let people know when I see this happening; because I am trying to be considerate of other people's time and effort.

I appreciate the help and time of people who r helping me here...I guess u r the one who is being rude!

Originally Posted by jeffcobb

Well aside from the total lack of indentation, the solution you have looks to be 10x more complex than it needs to be. However I suspect the root of your problems is less in the replacement code and more in how you are interpreting the command line arguments. If you are on Linux (or other NIX-like system) I would suggest using getopt() to handle the command line arguments and also use quotes to separate them. In your example you are just doing:

progname I like studying like hate

But that will result in 5 command line arguments, one for each space-delimited token. Something like:
progname "I like studying" like hate

will work better since the arg 'I like studying' will be treated as a single item...with getopt() it makes it even cleaner so you can do:

progname --source "I like studying" --search key --replace hate

Thanks for your help...
I used " " for the input string and its all good now ...

Code:

 

#include <stdio.h>
#include <string.h>
int main (int argc,char *argv[]) {
char *p, *find, *replace;

p = argv[1];
find =argv[2];
replace =argv[3];
size_t len=strlen(p);
size_t s_len=strlen(find);
size_t r_len=strlen(replace);
char *current=p;
while ((current = strstr(p,find))) {
memmove(current + r_len , current + s_len,len - (current - p) - s_len + 1);
memcpy(current, replace, r_len);
}
++p;
printf("%s\n",argv[1]);
}