CPU Scheduling Algorithms. --- First come First serve(fcfs)

/* Simulate the following cpu scheduling algorithms.
    C. First come First serve(fcfs) when the arrival times are given    */

#include<stdio.h>
#include<conio.h>
void main()
{
    int i,bt[10],n,twt=0,z[20],at[10];
    int wt[10],sum=0,sum1=0;
    float avgt=0.00;
    clrscr();
    printf("\n Enter no. of Processes ::");
    scanf("%d",&n);
    printf("\n Enter the %d burst times::",n);
    for(i=0;i<n;i++)
    {
        printf("\n\n Enter burst and arrival times for process%d::",i+1);
        scanf("%d%d",&bt[i],&at[i]);
    }
    for(i=0;i<n;i++)
    {
        if(i==0)
        {
            wt[i]=0;
            sum=sum+bt[i];
        }
        else
        {
            wt[i]=sum-at[i];
            sum=sum+bt[i];
        }
        sum1=sum1+bt[i];
        z[i]=sum1;
    }
    printf("\n\n----------------------------------------------\n");
    printf("\n\tPNo\tbt\tat\twt\n");
    printf("\n----------------------------------------------\n");
    for(i=0;i<n;i++)
    {
        twt+=wt[i];
        printf("\n\n\tP%d\t%d\t%d\t%d\n",i+1,bt[i],at[i],wt[i]);
    }
    printf("\n----------------------------------------------\n");
    avgt=(float)twt/(float)n;
    printf("\n\nGannt Chart ::\n\n");
    printf("\t0");
    for(i=0;i<n-1;i++)
        printf("%4d",z[i]);
    printf("\n\n Total waiting time is ::%d",twt);
    printf("\n\n Average waiting time is ::%f",avgt);
    getch();
}
 /*Input and OutPut:-
 Enter no. of Processes ::4
 Enter the 4 burst times::
 Enter burst and arrival times for process1::10 0
 Enter burst and arrival times for process2::4 1
 Enter burst and arrival times for process3::6 2
 Enter burst and arrival times for process4::3 4
----------------------------------------------
    PNo     bt      at      wt
----------------------------------------------
    P1      10      0       0
    P2      4       1       9
    P3      6       2       12
    P4      3       4       16
----------------------------------------------
Gannt Chart ::
    0  10  14  20

 Total waiting time is ::37
 Average waiting time is ::9.250000*/