public class FourNumberGen { public static void main(String args[]){ int i,j,k,l; System.out.println("With Repetition: "); for(i = 0; i<=9; i++){ for(j = 0; j<=9; j++){ for(k = 0; k<=9; k++){ for(l = 0; l<=9; l++) { System.out.print(i+""+j+""+k+""+l+" "); } } } } for(i=0;i<10;i++){ System.out.println(" "); } System.out.println("Without Repetition: "); for(i = 0; i<=9; i++){ for(j = 0; j<=9; j++){ for(k = 0; k<=9; k++){ for(l = 0; l<=9; l++) { if((i!=j)&(i!=k)&(i!=l)&(j!=k)&(j!=l)&(k!=l)){ System.out.print(i+""+j+""+k+""+l+" "); } } } } } } }