No,we can write a program with out main function, this function is the main function which usually help OS to kill the process that has executed.   

#include

#define nishant(s,t,u,m,p,e,d)m##s##u##t

#define nirmal nishant(a,n,i,m,a,t,e)

int nirmal()

{

printf("HELLO Nirmal");
printf("\n");
}

#include

#define nishant(s,t,u,m,p,e,d)m##s##u##t

#define nirmal nishant(a,n,i,m,a,t,e)

int nirmal()

{

printf("HELLO Nirmal");
printf("\n");
}