Question

write C program to implement the priority queue with the operation insert

Answer 1

#include<stdio.h>
#define N 20
int Q[N],Pr[N];
int r = -1,f = -1;
void enque(int data,int p)//Enqueue function to insert data and its priority in queue
{
        int i;
        if((f==0)&&(r==N-1)) //Check if Queue is full
                printf("Queue is full");
        else
        {
                if(f==-1)//if Queue is empty
                {
                        f = r = 0;
                        Q[r] = data;
                        Pr[r] = p;

                }
                else if(r == N-1)//if there there is some elemets in Queue
                {
                        for(i=f;i<=r;i++) { Q[i-f] = Q[i]; Pr[i-f] = Pr[i]; r = r-f; f = 0; for(i = r;i>f;i--)
                                {
                                        if(p>Pr[i])
                                        {
                                                Q[i+1] = Q[i];
                                                Pr[i+1] = Pr[i];
                                        }
                                        else
                                                break;
                                        Q[i+1] = data;
                                        Pr[i+1] = p;
                                        r++;
                                }
                        }
                }
                else
                {
                        for(i = r;i>=f;i--)
                        {
                                if(p>Pr[i])
                                {
                                        Q[i+1] = Q[i];
                                        Pr[i+1] = Pr[i];        
                                }
                                else
                                        break;
                        }
                        Q[i+1] = data;
                        Pr[i+1] = p;
                        r++;
                }       
        }

}
void print() //print the data of Queue
{
int i;
        for(i=f;i<=r;i++)
        {
                printf("\nElement = %d\tPriority = %d",Q[i],Pr[i]);
        }
}
 
int main()
{
        int opt,n,i,data,p;
        printf("Enter Your Choice:-");
        do{
                printf("\n\n1 for Insert the Data in Queue\n2 for show the Data in Queue \n0 for Exit \n");
                scanf("%d",&opt);
                switch(opt){
                        case 1:
                                printf("\nEnter the number of data");
                                scanf("%d",&n);
                                printf("\nEnter your data and Priority of data \n");
                                i=0;
                                while(i<n){
                                        scanf("%d %d",&data,&p);
                                        enque(data,p);
                                        i++;
                                }
                                break;
                        case 2:
                                print();
                                break;
        
                        case 0:
                                break;
                        default:
                                printf("\nIncorrect Choice");

                }
        }while(opt!=0);
        return 0;
}

Output screen:

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