Algorithm
Step 1:Start.
Step 2:Declare variables num,flag,i,j.
Step 3:Input and read the limit,num.
Step 4:If num=1 then
4.1)Print there are no prime numbers.
Step 5:Else
5.1)Initialize i=2.
5.2)while(i<=num) repeat steps a to g.
a)Initialize flag=0 and j=1.
b)while(j<=i) repeat steps b.1 to b.3
b.1)if(i%j==0) then increment flag by 1.
b.2)End if.
b.3)Increment j by 1.
c)End while.
d)If flag=2 then print the number,i.
e)End if.
g)Increment i by 1.
5.3)End while.
Step 6:End if.
Step 7:Stop.
Program
#include<stdio.h>
#include<conio.h>
void
main()
{
int num,flag,i,j;
clrscr();
printf("Enter the limit:\n");
scanf("%d",&num);
if(num==1)
{
printf(“No Prime numbers”);
}
else
{
printf("Prime Numbers are \n");
for(i=2;i<=num;i++)
{
flag=0;
for(j=1;j<=i;j++)
{
if(i%j==0)
flag++;
}
if(flag==2)
printf("%d\n",i);
}
}
getch();
}
Output
Enter the limit:
20
Prime Numbers are
2
3
5
7
11
13
17
19
what is flag
ReplyDeletePrime numbers have only two factors, one and the number itself. The 'flag' represents the number of the factors.
Delete