Using Strings in C strtok and strcmp errors

Anubhab123 · 12-18-2005, 06:26 PM

Hello all i'm having a problem with the function strtok().i'm trying to compare the tokenized string with another string however when i use the function strcmp() it generates a segmentation fault
i wrote this

void check(FILE *file){
char buf[100]
char store[100][100];
int n=0;
char *token;
char *name="DOG";

while(fgets(buf,sizeof(buf),file)!=NULL){
strcpy(store[n],buf);
n++;
}

while(n>=0){
token=strtok(store[n]," ");
if(strcmp(token,name)==0){
printf("BINGO");
}
n--;
}

}

A file is properly passed in and it looks like

THE DOG IS BIG!

my big problem is that it keeps saying segmentation fault whenever i try to call strcmp with token.I tried making another string that isnt tokenized or anything and tried the method with that and it worked but for some reason if its a tokenized string it gives the segfault error.Any help would be appreciated!

jtshaw · 12-18-2005, 07:03 PM

I'm not sure exactly what you are looking to do here, but if your trying to find DOG in the each line check out then you probably want something that looks like this:

Code:

void check(FILE *file)
{
        char buf[100];
        char store[100][100];
        int n=0;
        char *token;
        char *name="DOG";

        while(fgets(buf,sizeof(buf),file)!=NULL){
                strcpy(store[n],buf);
                n++;
        }

        while(n>=0){
                token=strtok(store[n]," ");
                do {
                        printf ("Token = %s\n",token);
                        if(strncmp(token,name,strlen(name))==0){
                                printf("BINGO");
                        }
                } while ((token = strtok(NULL," ")) != NULL);
                n--;
        }
}

I attempted to use the function you provided and while it didn't compile (missing a semi-colon) it also didn't seg fault when I fixed it. I also switched the strcmp to a strncmp as it is always better to use the strncmp (much safer).

PS. Please use code blocks when you post code, it makes it easier for us to see!