Computing Prime Number

 

Today, we need to find a suitable prime number, such as mental computing, pen computing, and online tools? It may be easier to write it by yourself. It can be considered a leisure and entertainment experience during work. The code is simple and the performance is poor. We do not recommend that you calculate more than 100,000 of the quality.

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# Include <vector>

# Include <conio. h>

 

Void Prime (int max)

{

Std: vector <bool> isNotPrimes (max + 1 );

IsNotPrimes [0] = true;

IsNotPrimes [1] = true;

IsNotPrimes [2] = false;

 

For (int I = 2; I * 2 <= max; I ++)

{

For (int j = 2; j ++)

{

Int product = I * j;

If (product> max)

{

Break;

}

Else

{

IsNotPrimes [product] = true;

}

}

}

 

For (int I = 0, j = 0, count = isNotPrimes. size (); I <count; I ++)

{

If (! IsNotPrimes [I])

{

Printf ("% 4d", I );

J ++;

If (j % 10 = 0)

{

Printf ("\ n ");

}

}

}

}

 

Int main (int argc, char * argv [])

{

If (argc! = 2)

{

Printf ("% s <max> calculate 0 ~ Prime numbers between max \ n ", argv [0]);

_ Getch ();

Return 0;

}

 

Int max = atoi (argv [1]);

If (max <2)

{

Printf ("no result \ n ");

_ Getch ();

Return 0;

}

 

Prime (max );

_ Getch ();

 

Return 0;

}

From: Guo yuefeng's column