Code:

//add int m to the list of int variables
for(i=0, m=0;i<10;i++) //not i=1;i<=10: THIS IS ** SPARTA!! ** -- ok, C then ;)
{
for(j=0;j<15;j++)
{
k=a[i][j];
if(isPrime(k))
{
//B[++m] = k;
B[m++] = k; //Thanks Anduril!
printf("%d";&B[m] //??
printf("%d is prime", k);
}// close if
}
}//- close for
/*function isPrime */
int isPrime(int k) {
sqr = sqrt(k);
int i, j;
for(i=2;i<=sqr;i++) {
//add your mod test in here k mod i
//if k mod i equals 0 then return 0
}
//no divisor was found for k, it's prime
//so return 1
}

i think this is what you're suggesting. thank you very much.

i didnt even know there is a IsPrime() function.

And i still dont know if i'm allowed to use that.

isPrime is the name I use for it - C has no isPrime() function as part of it's standard library.

Good name though, huh?