Question

How can I remove first two elements of a string array?
I have a code which is something like this.

char *x[10];
..............
..............
..............
char *event[20];
event[0]=strtok(x[i]," ");
event[1]=strtok(NULL," ");
event[2]=strtok(NULL," ");
event[3]=strtok(NULL," ");
event[4]=strtok(NULL," ");
event[5]=strtok(NULL," ");
for(i=2;i<length;i++)
{
    strcpy(event[i-2],event[i]);
}

I observed that only event[0] has proper values. I printed the contents of event[][] before for loop and it displays correctly. Could you please tell me why this is wrong? and a possible solution?

Answer 1

You should not be using strcpy() in this code. The API strtok() will return you a pointer to the delimited token discovered within the original source buffer after terminating at the discovered delimiter. Therefore, you’re using strcpy() where you should not be.

Your events[] array has pointers returned from strtok(). Just throw out the first two pointers and move the others down:

for(i=2;i<length;i++)
    event[i-2] = event[i];
length -= min(length, 2);

Note: the min() is required to ensure your length, signed or unsigned, never wraps below zero (if signed) or UINT_MAX (if unsigned) in the event length is undersized on entry.