Help! strcmp is lying to me when fed strtok results
strcmp, when fed the resul开发者_JS百科ts of strtok, in the following code seems to be blatantly lying to me.
int fSize;
char * buffer=NULL;
char * jobToken = "job";
char * nextToken=NULL;
job * curJob=NULL;
struct node * head=NULL;
struct node * parseList(FILE* file){
fseek(file,0,SEEK_END);
fSize=ftell(file);
buffer = (char*)malloc(fSize+1);
printf("%d chars: reading buffer now:\n",fSize);
fseek(file,0,SEEK_SET);
fread (buffer,1,fSize,file);
nextToken = strtok(buffer, " \n");
while (nextToken!=NULL){
printf("**Running Token: %s**\n",nextToken);
if (strcmp(nextToken,jobToken)){
printf("Accepted %s as %s\n",nextToken,jobToken);
}else{
printf("not %s, %s\n",jobToken,nextToken);
}
printf("End of state - %s\n",nextToken);
nextToken = strtok(NULL, " \n");
}
free (buffer);
return NULL;
}
With this input in a file in the parseList parameters:
job 23
job 10
Gives this output:
14 chars: reading buffer now:
**Running Token: job**
not job, job
End of state - job
**Running Token: 23**
Accepted 23 as job
End of state - 23
**Running Token: job**
not job, job
End of state - job
**Running Token: 10**
Accepted 10 as job
End of state - 10
LIES!
strcmp
returns 0 when the strings you are comparing are equal. You need to use if (!strcmp(...))
.
strcmp returns 0 when the strings are equal. See: http://www.elook.org/programming/c/strcmp.html
Not related to your question, but a couple of points:
- After the
fread()
, you should setbuffer[fSize] = 0;
, otherwise it's not a string. - Determining the numbers of characters to read in either a text file or a binary file using
fseek(file,0,SEEK_END);
isn't guaranteed to work.
Personally, I would write the malloc()
call as:
buffer = malloc(fSize+1);
because that will warn me if I forgot to #include <stdlib.h>
, and is easier to read. The cast is not required in C.
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