1.while

#include <iostream>

using namespace std;

int main () {

inti,j,n,m;

i=2;

while(i<101)

{

m=1,n=i/2;j=2;

while(j<=n)

{

if(i%j==0)

{

m=0;

break;

}

j++;

}

if(m)

cout<<i<<" ";

i++;

}

}

2.do....while

#include<iostream.h>

void main()

{

inti,j,n,m;

i=2;

do

{

m=1;

n=i/2;

j=2;

do

{

if(i%j==0)

{

m=0;

break;

}

j++;

}

while(j<=n);

if(m)

cout<<i<<" ";

i++;

}

while(i<101);

}

3.for

# include<iostream.h>

void main()

{

inti,j,n,m;

for(i=2;i<101;i++)

{

m=1;

n=i/2;

for(j=2;j<=n;j++)

{

if(i%j==0)

{

m=0;

break;

}

}

if(m)

cout<<i<<" ";

}

}