Concat 4 integers into one integer

Concat 4 integers into one integer

Hi i am trying to concatinate 4 integers one integer. I used the
concatinate function found here :
http://stackoverflow.com/a/12700533/2016977
My code:
unsigned concatenate(unsigned x, unsigned y) {
unsigned pow = 10;
while(y >= pow)
pow *= 10;
return x * pow + y;
}
void stringtoint(){
struct router *ptr;
ptr=start;
while(ptr!=NULL){
int a;
int b;
int c;
int d;
sscanf(ptr->ip, "%d.%d.%d.%d", &a, &b, &c, &d);
int num1 = concatenate(a,b);
int num2 = concatenate(c,d);
int num3 = concatenate(num1,num2);
printf("%d\n",num3);
ptr=ptr->next;
};
}
The problem:
I am dealing with IP address numbers e.g. 198.32.141.140 i am breaking
them down to 4 integers and concatenate them to form 19832141140, however
my concatenate function is doing maths on the larger number like
198.32.141.140 (becomes) - >-1642695340 but it is concatenating the IP
which are small numbers e.g. 164.78.104.1 becomes 164781041 (which is
correct)
How should i solve the problem, basically i am trying to make a string of
IP e.g. 198.32.141.140 into an integer number 19832141140