## INDEX

### C program to find prime numbers between two numbers

C program or code to find prime numbers between two numbers

#include<stdio.h>

int main(){

int num,i,count,min,max;

printf("Enter min range: ");
scanf("%d",&min);

printf("Enter max range: ");
scanf("%d",&max);

for(num = min;num<=max;num++){

count = 0;

for(i=2;i<=num/2;i++){
if(num%i==0){
count++;
break;
}
}

if(count==0 && num!= 1)
printf("%d ",num);
}

return 0;
}

Sample output:
Enter min range: 10
Enter max range: 50
11 13 17 19 23 29 31 37 41 43 47

Algorithm:

Definition of prime number:

A natural number greater than one which has not any other divisors except 1 and itself is called prime number. In other word we can say which has only two divisors 1 and number itself. For example: 5

Their divisors are 1 and 5.

Note: 2 is only even prime number.

Logic for prime number in c
We will take a loop and divide number from 2 to number/2. If the number is not divisible by any of the numbers then we will print it as prime number.

Example of prime numbers : 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199 etc.

Unknown said...

change i!=0 with i>1, will work with neg integers too

Unknown said...

try this also
#include
#include
using namespace std;
int main()
{
int a,i,n,j,b,k=0;
cout<<"enter the first range :";
cin>>a;
cout<<"enter the last range :";
cin>>b;
for(i=a;i<=b;i++)
{
k=0;
for(j=1;j<=i;j++)
{
n=i%j;
if(n==0)
{
k=k+1;
if(k==2 && i==j )
{
cout<<"i="<<i<<endl;
}
}

}

}
return 0;
getch();

}

DEVRAJ ANAND said...

why do wetake count as variable