Non-Preemptive SJF (Shortest Job First) - Drawing Gantt Chart

/*

                implementing non Preemptive sjf

                non Preemptive shortest job first.

*/

/*

                processes are assumed to be in order P0, P1, P2 and so on.

*/

void drawGanttChart();

#include<stdlib.h>

#include<stdio.h>

int numberOfProcesses,totalCPUBurstTime,*arrivalTime,*CPUBurstTime,*processNumber,minimumArrivalTime;

float averageWaitingTime=0,averageTurnAroundTime=0;

int main()

{

                int i,j,temp;

               

                printf("Enter the number of processes : ");

                scanf("%d",&numberOfProcesses);

                arrivalTime=(int*)malloc(sizeof(int)*numberOfProcesses);

                CPUBurstTime=(int*)malloc(sizeof(int)*numberOfProcesses);

                processNumber=(int*)malloc(sizeof(int)*numberOfProcesses);

               

                minimumArrivalTime=2147483647;

                for(i=0;i<numberOfProcesses;i++)

                {

                                processNumber[i]=i;

                                printf("\nEnter the data for process number : %d\n",i);

                                printf("\n");

                                printf("Arrival Time   : ");

                                scanf("%d",&arrivalTime[i]);

                                printf("CPU Burst time : ");

                                scanf("%d",&CPUBurstTime[i]);

                                totalCPUBurstTime+=CPUBurstTime[i];

                                if(minimumArrivalTime>arrivalTime[i])

                                                minimumArrivalTime=arrivalTime[i];

                }

               

                /*

                                implementing bubble sort algorithm

                */

               

                for(i=0;i<numberOfProcesses;i++)

                {

                                for(j=0;j<numberOfProcesses-i-1;j++)

                                {

                                                if(CPUBurstTime[j]>CPUBurstTime[j+1])

                                                {

                                                                temp=arrivalTime[j];

                                                                arrivalTime[j]=arrivalTime[j+1];

                                                                arrivalTime[j+1]=temp;

                                                               

                                                                temp=CPUBurstTime[j];

                                                                CPUBurstTime[j]=CPUBurstTime[j+1];

                                                                CPUBurstTime[j+1]=temp;

                                                                                               

                                                                temp=processNumber[j];

                                                                processNumber[j]=processNumber[j+1];

                                                                processNumber[j+1]=temp;

                                                }

                                }

                }

               

                for(i=0;i<numberOfProcesses;i++)

                {

                                printf("P%d -> %d,%d\n",processNumber[i],arrivalTime[i],CPUBurstTime[i]);

                }

               

                drawGanttChart();

               

}

void drawGanttChart()

{

                const int maxWidth=100;

                int scalingFactor,i,counter,tempi,currentTime;

                printf("The gantt chart for the given processes is : \n\n");

               

                scalingFactor=maxWidth/totalCPUBurstTime;

                for(i=0;i<scalingFactor*totalCPUBurstTime+2+numberOfProcesses;i++)

                {

                                printf("-");

                }

                printf("\n|");

                counter=0,tempi=0;

                for(i=0;i<scalingFactor*totalCPUBurstTime;i++)

                {

                                if(i==CPUBurstTime[counter]*scalingFactor+tempi)

                                {

                                                counter++;

                                                tempi=i;

                                                printf("|");

                                }

                                else if(i==(CPUBurstTime[counter]*scalingFactor)/2+tempi)

                                {

                                                printf("P%d",processNumber[counter]);

                                }

                                else

                                {

                                                printf(" ");

                                }

                               

                }

                printf("|");

                printf("\n");

                for(i=0;i<scalingFactor*totalCPUBurstTime+2+numberOfProcesses;i++)

                {

                                printf("-");

                }

                printf("\n");

                /* printing the time labels of the gantt chart */

                counter=0;

                tempi=0;

                currentTime=minimumArrivalTime;

                printf("%d",currentTime);

                for(i=0;i<scalingFactor*totalCPUBurstTime;i++)

                {

                                if(i==CPUBurstTime[counter]*scalingFactor+tempi)

                                {

                                               

                                                tempi=i;

                                                currentTime+=CPUBurstTime[counter];

                                                averageWaitingTime+=currentTime;

                                                counter++;

                                                printf("%2d",currentTime);

                                }

                                else

                                {

                                                printf(" ");

                                }

                }

                currentTime+=CPUBurstTime[counter];

               

                printf("%2d\n\n",currentTime);

                averageWaitingTime=averageWaitingTime/numberOfProcesses;

                averageTurnAroundTime=averageWaitingTime+totalCPUBurstTime/numberOfProcesses;

               

                printf("Average waiting Time     : %f\n",averageWaitingTime);

                printf("Average Turn Around Time : %f\n",averageTurnAroundTime);

}