FCFS ALGORITHM

First we tried to calculate the response time and complete time
for the first process response time is equal to arrival time and complete time is equal to the sum of response time and burst time.
For  next process 
                            if arrival time is equal to the complete time of the previous process then there will be  no idle time and response time is equal to the complete time of the previous process
                           if arrival time is greater than the complete time of the previous process then there will be the idle time and the response time will equal to the arival time of the porcess
                           if arrival time is less than the complete time of the previous process then there will again no idle time and response time is equal to to the complete time of the previous time

For all the above case 
complete time =response+burst time
waiting time=response time-arrival time


#include<stdio.h>
#include<stdlib.h>
struct process
{
       int at; //arival time
       int bt; //burst time
       int rt; //response time
       int  c; //completed time
       int wt; //waiting time
       int trt;
       };  //structure to hold all the attributes associated with process

void display(struct process *p)//Function to display all the attributes of the process
{  
    int i=1;
    while(1)
    {
        printf("Arrival time%d  ",p[i].at);
        printf("Burst Time%d  ",p[i].bt);
        printf("Response Time%d  ",p[i].rt);
        printf("comlete Time%d  ",p[i].c);
        printf("waiting Time%d  ",(p[i].rt-p[i].at));
        printf("\n\n");
        i++;
        if(i==4)
        break;
    }
}    
void fcfs(struct process *p)//first position of the array is ignored and counting has started from index value one
{
     if((p[1].at)>0)
      printf("Idle   0-%d\n",p[1].at);
      p[1].rt=p[1].at;
      p[1].wt=0;
      p[1].c=(p[1].at+p[1].bt);
      int i=2;
      while(1)
      {
     
             if(p[i].at==p[i-1].c)
             p[i].rt=p[i-1].c;
            
             if((p[i].at)>(p[i-1].c))
             {
             printf("Idle   %d-%d\n",p[i-1].c,p[i].at);
             p[i].rt=p[i].at;
             p[i].c=p[i].rt+p[i].bt;
              }
             
              if(p[i].at<p[i-1].c)
              {
              p[i].rt=p[i-1].c;
              p[i].c=p[i].rt+p[i].bt;
              }
             
              i++;
              if(i==4)
              break;
        }
 }
main()
{
      struct process p[100];
      puts("Enetr the process arival time and burst time");
      int i=0;
      while(1)
      {
      i++;
      scanf("%d",&(p[i].at));
      scanf("%d",&(p[i].bt));
      if(i==3)
      break;
      }
      fcfs(p);
      display(p);
      }