function with arguments with return value

/*function with   arguments  with return value*/

#include<conio.h>

#include<stdio.h>

calsum(int ,int,int);

void main()

{

int a,b,c,sum;

printf("\nEnter any three number");

scanf("%d%d%d",&a,&b,&c);

sum=calsum(a,b,c);

printf("\n Sum=%d",sum);

getch();

}

calsum(int x,int y,int z)

{

int d;

d=x+y+z;

return(d);

}