C программа для разделения электронной почты te на основное и доменное имя

hello this is my assignment i have to write a c program to split an email into main and domain name.
please anyone can help me to write a code that split the email.  

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
   main() 
 {
	FILE*fp=fopen("m.csv","r+");
     const char s[2]=",";              // here s is constant. It can't be reasign another string but we can assign another character value at s[index]
	char*token;                        //  Char* is a pointer that points to a token. Tokens are the smallest units that make a complete C program
	int i;
	if(fp!=NULL) {
		char line[30];
		while(fgets(line,sizeof line,fp)!=NULL) {
			token=strtok(line,s);    // Strtok break the String into tokens. It search for comma and when it is found it stores the preceding value into an array and so on 
			for(i=0;i<2;i++) {                        
				if(i==0) {
					printf("%s",token);
					token=strtok(NULL,s);
				} else {
					printf("%s",(token));
				}
			}
		}
		fclose(fp);
	} 
}