compare strings not working

I am somewhat new to C programming, but this looks like it should work. I am using MS VS .Net 2002. When I put my mouse over the variable, the strings match up, but when I compare them, the comparison does not equal each other. What I do here is parse a string, then I need to compare it. so if the string is "123 W Main St". It seems to parse ok, but when i come to the "W", I need to compare it with "W" and it does not work.

Code:

---

char * Grab_String(char* string, int length)
{
        char *ip;
        int i = 0;

        ip = (char *) malloc(length*sizeof(char *));
        while (i < length)
        {
                ip[i] = string[i];
                i = i++;
        }
        ip[i] = '\0';

        return ip;
}


char *ParseDelimiter (char *addr_string, char delimiter)
{
        char *field;
        char hold;
        int seperator;
        int str_len;
        int i = 0;
        int x=0;
        bool ok=false;

        str_len = strlen(addr_string);
        while (i <= str_len)
        {
                if (addr_string[i] == delimiter)
                        break;
                i = i++;
        }       

        field = Grab_String(addr_string, i);

        if ("W"==field)  //////HERE IS THE CODE THAT DOES NOT WORK
        {
                ok=true;
        }

        return field;
}

---

Thanks for helping.

George

You must use strcmp to compare strings.

> ip = (char *) malloc(length*sizeof(char *));
1. Don't cast the result of malloc in C - see the FAQ
2. you use the size of the type, not the size of the pointer
3. you forgot to count the \0 at the end

Try
ip = malloc( (length+1) * sizeof *ip );

> i = i++;
This is just wrong
Use either
i++;
or
i = i + 1;

Quote:

---

Originally Posted by hk_mp5kpdw

You must use strcmp to compare strings.

---

strcmp() returns 0 if the strings are equal.

Code:

---

if(strcmp(string1, string2) == 0) {}

---

this is something terribly wrong with this function, but i dont know what it is. If you see, where I commented out the address, if I uncomment it, the function works fine. The other strange thing is that when i am in the dubugger, the variable returned will be the correct one, but the compare strings does not work. If I uncomment, and use the hard code the strings compare fine. Please help, my head hurts from banging it on the desk.

Code:

---


char * left(char * string, int length)
{
        char *ip;
        int i = 0;

        ip = (char *) malloc((length*sizeof(char)));
        while (i < length)
        {
                ip[i] = string[i];
                i++;
        }
        ip[i] = '0';

        //ip = "2406 W OCEAN FRONT ST";

        return ip;
}

---

You should pass a previously allocated buffer to your function, because returning local stack data is dangerous and heap data must be free()'ed. You can assume your strings are null-terminated and remove the length parameter probably. Your implementation will end up looking very similar to strcpy (is this what your function intends?), which you will notice also takes a destination and source buffer.

> ip = (char *) malloc((length*sizeof(char)));
Well if you're just going to keep ignoring people, stop asking questions.

Code:

---

ip[i] = '0';

---

Maybe you want '\0'?

Yes, and see Salem's first post.