Laboratoare Java

mport java.io.*;

class SumaNrPrime

{

public static void main(String args[ ]) throws IOException{

String s;

int i,j,k,l,m,n,suma,nr_div,nr_desc=0;

int nr_prime[]=new int[99];

int c[]=new int[20];

boolean prim;

System.out.print("n");

do

{

System.out.print("Dati numarul care se doreste a fi descompus, n=");

s=citireSir();

n=Integer.valueOf(s).intValue();

System.out.print("n");

if (!(n>0))

System.out.println("Eroare! Dati valori naturale pozitive numarului n.");

} while (n<=0);

do

{

System.out.print("Dati numarul de termeni ai descompunerii, k=");

s=citireSir();

k=Integer.valueOf(s).intValue();

System.out.print("n");

if (!(k>2))

System.out.println("Eroare! Dati valori naturale >2 numarului k.");

} while (k<=2);

i=0;

for(j=1;j<=n;j++)

{

if ((j==1) | (j==2))

prim=true;

else

{

prim=true;

nr_div=0;

for(l=1;l<=j;l++)

if ((j%l)==0)

nr_div++;

if (!(nr_div==2))

prim=false;

}

if (prim==true)

{

i++;

nr_prime[i]=j;

}

}

for(j=1;j<=k;j++)

c[j]=j;

suma=0;

for(j=1;j<=k;j++)

suma=suma+nr_prime[c[j]];

if (suma==n)

{

nr_desc++;

System.out.print(nr_desc+")."+n+"=");

for(j=1;j<k;j++)

System.out.print(nr_prime[c[j]]+"+");

System.out.print(nr_prime[c[k]]);

System.out.print("n");

}

do

{

j=k;

while ((c[j]==i-k+j) && (j>0))

j--;

if (j>0)

{

c[j]++;

for(l=j+1;l<=k;l++)

c[l]=c[l-1]+1;

suma=0;

for(l=1;l<=k;l++)

suma=suma+nr_prime[c[l]];

if (suma==n)

{

nr_desc++;

System.out.print(nr_desc+")."+n+"=");

for(l=1;l<k;l++)

System.out.print(nr_prime[c[l]]+"+");

System.out.print(nr_prime[c[k]]);

System.out.print("n");

}

}

} while (j>0);

if (nr_desc==0)

System.out.println("Problema nu admite solutii.");

}

static String citireSir() throws IOException

{

String h;

InputStreamReader

f=new

InputStreamReader(System.in);

BufferedReader g=new

BufferedReader(f);

h=g.readLine();

return h;

}

}