C :

#include <stdio.h>
int main() {
        int prime[100];
        int i, j;
        for (i = 0;i < 100;i++)
                prime[i] = 1;
        prime[0] = prime[1] = 0;
        for (i = 2;i < 100;i++) {
                if (prime[i] == 1) {
                        for (j = i + i;j < 100;j += i)
                                prime[j] = 0;
                }
        }
        for (i = 0;i < 100;i++)
                if (prime[i] == 1)
                        printf("%d ", i);
        puts("");
        return 0;
}

C++ :

#include <stdio.h>
int main() {
	int prime[100];
	int i, j;
	for (i = 0;i < 100;i++)
		prime[i] = 1;
	prime[0] = prime[1] = 0;
	for (i = 2;i < 100;i++) {
		if (prime[i] == 1) {
			for (j = i + i;j < 100;j += i)
				prime[j] = 0;
		}
	}
	for (i = 0;i < 100;i++)
		if (prime[i] == 1)
			printf("%d ", i);
	puts("");
	return 0;
}

Pascal :

const Num=100;
var
  a:array[1..100] of longint;
  i,j:longint;
begin
  for i:=2 to Num do a[i]:=1;
  for i:=2 to 10 do
    for j:=2 to Num div 2 do
      if( (a[i]=1) and (i*j<=Num) ) then 
        a[i*j]:=0;
  for i:=2 to Num do 
    if(a[i]=1) then write(i,' ');
  writeln;
end.

Java :

public class Main {
	public static void main (String[] args) {
	    for(int i=2;i<=100;i++){
	    	boolean is=true;
	    	for(int d=2;d<=i/2;d++){
	    		if(i%d==0){
	    			is=false;
	    			break;
	    		}
	    	}
	    	if(is)
	    		System.out.print (i+" ");
	    }
	    System.out.println ();
	}
}