Write a program that count total prime numbers from 1 to n.

#include<stdio.h>
#include<conio.h>
#include<math.h>

void main()
{
    int n,i,j,p,t,k=0;
    clrscr();
    printf("Enter 1st number, n = ");
    scanf("%d",&n);

    for(i=2;i<=n;i++)
    {
       p=1;
       t=sqrt(i);

       for(j=2;j<=t;j++)
          if(i%j==0)
          {
             p=0;
         break;
          }
       if(p==1)
          k++;
    }
    printf("Total Prime number = ",k);

    getch();
}

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Copy & paste this code in your TC & run, then you will get output.......
If you have any problem please comment below.........