FCFS (First Come First Serve) CPU Scheduling

#include<stdio.h>
#include<stdlib.h>
#include<conio.h>
struct Process //structure for processes
{
 int burst;
 int time;
};
//--------functions------------------------
//a function that displays the processes and their burst time
int validate(int processInput)
{
	if(processInput == 0 || processInput>20)
		return 0;
	else
		return 1;
}
void heading()
{
	gotoxy(18,3);
	printf(" ---------------------------------------\n");
	gotoxy(18,4);
	printf("| FIRST COME FIRST SERVE CPU SCHEDULING |\n");
	gotoxy(18,5);
	printf(" ---------------------------------------\n");
	gotoxy(18,6);
	printf("| 1 - Use this program         |\n");
	gotoxy(18,7);
	printf("| 2 - CREDITS             |\n");
	gotoxy(18,8);
	printf("| 3 - Exit               |\n");
	gotoxy(18,9);
	printf(" ---------------------------------------\n");
	gotoxy(18,10);
  printf("Enter your choice(1-4):");
}
void displayProcess(Process p[], int processInput, int sum, float &awt)
{
int i,index=1,yAxis=12;
	gotoxy(18,12);
	printf("Processes\tBurst Time\tWaiting Time\n");
 for(i=0;i<processInput;i++)
 {
	gotoxy(18,yAxis+=1);
 printf("\tP%d\t%5d\t%15d\n", index, p[i].burst, p[i].time);
 index++;
 }
 gotoxy(18,yAxis+2);
 printf("Total Waiting Time = %d\n",sum);
 gotoxy(18,yAxis+3);
 printf("Average Waiting Time = %.2f",awt);
}
//a function that generates random burst for each processes
void randomBurst(Process p[], int processInput)
{
int i,burstTime;
	randomize();//call randomize function
 for(i=0;i<processInput;i++)
 {
	burstTime=rand()%10; //generate random number
  p[i].burst=burstTime; //assign the random number to each process' burst time
 }
}
//a function that computes the waiting time of each process, sum and average of waiting time
void waitingTime(Process p[],int processInput,int &sum, float &awt)
{
int i;
	p[0].time = 0; //always assign zero waiting time for process 1
	p[1].time=p[0].burst; //assign the burst time of process 1 to process 2
  sum=p[1].time; //sum stores the waiting time of process 2
 for(i=2;i<processInput;i++)//assign waiting time for the succeeding processes
 {      //process1 burstTime + process1 waiting time
	p[i].time=(p[i-1].burst + p[i-1].time);
	sum += p[i].time; 
 }
 
}
main()
{
 Process p[20];
 int processInput,burstTime,i,j,sum=0,choice;
 float awt=0.00;
 do
 {
 heading();
 scanf("%d",&choice);
	if(choice == 1)
	{
		clrscr();
		gotoxy(18,10);
		printf("Enter the Number of processes(1-20):");
		scanf("%d",&processInput);
			if(validate(processInput) == 1)
			{
				randomBurst(p,processInput);
				waitingTime(p,processInput,sum,awt);
				awt = (sum/processInput);
				displayProcess(p,processInput,sum,awt);
				getch();
				clrscr();
				fflush(stdin);
			}
			else
			{
			clrscr();
     }
	}
	else if(choice == 2)
	{
	clrscr();
	gotoxy(18,10);
	printf("\tCreated by:\n");
	gotoxy(18,11);
	printf("Created By:\n");
	gotoxy(18,12);
	printf("Blueorange Tekknologee\n");
	getch();
	clrscr();
	}
 }
 while(choice!=3);
 clrscr();
 gotoxy(32,10);
 printf("GOoDByE!");
}