I was given a problem to find out all the prime numbers within a range.Just after I wrote the program I found numerous other codes to solve the problem.I am interested to know is my algorithm efficient?is it like sieve filtration?(before writing this code I had no clear idea on sieve filtration method)or the algorithm I used is a crap.:P


    #include<iostream.h>
    

    void prime_gen(int a,int b)
    {


	    int array[4]={2,3,5,7},holder[1000000]={0},count=0,length=0;
	
	    for(int i=a;i<b;i++)
	    {
		    for(int j=0;j<4;j++)
		    {
			    if(i==array[j])
			    {
				    break;
			    }
			    else 
			    {
				    if(i%array[j]==0)
				    {
					    count++;
					
				    }
			    }
		    }
		    if(count==0)
		    {
			    if(i>1)
			    {
				    holder[length++]=i;
			    }
			    else
			    {
				    length=0;
			    }
		    }
		    count=0;
	    }
	
	    if(length==0)
	    {	
		    cout<<"No prime numbers exist within the range";
		    cout<<"\n";
		
	    }
	    else 
	    {
			    cout<<"Prime numbers are:";
			    for(int i=0;i<length;i++)
			    {
				    cout<<holder[i]<<"\t";
			    }
			
			    cout<<"Total count:"<<length<<endl;
			
	    }

	
    }

    int main()
    {
	
	    int a,b;
	
	    cout<<"Put the first integer:";
	    cin>>a;
	
	    cout<<"Put the second integer:";
	    cin>>b;
	
	    prime_gen(a,b);	
	
    }