Call By Value And Call By Reference:- 1- Call By Value -: In call by value each of the actual arguement in the calling function is copied to the formal arguement. The change made in the formal arguement have no effect on the values of actual arguement in calling function. 2- Call By Reference -: In call by reference the address of actual arguement in the calling function is copied to the formal arguement. The change made in the formal arguement, made change on the values of actual arguement in calling function. img credit: google image Example -: #include<stdio.h> #include<conio.h> main() {int x=0,y=0,res=0; printf("Enter the value of x and y:-"); scanf("%d %d ",&x,&y); printf("\n x=%d,y=%d"x,y); res= swap_value(intx,inty) printf("\n Now x=%d y=%d"x,y); getch(); } int swap_value(intx,inty) {int t=0; printf("\n here x=%d y=%d",x,y); t=x; x=y; y=t; printf("\n now x=%d t=%d y=%d",x,t,y); } Output -: Ente...