[SickAttack]

Here:
Version without bool:

pawn Код:

// On top of your gamemode:
#define MAX_LOTTO_NUMBERS 100
new LottoNumbers[MAX_LOTTO_NUMBERS];

// This goes in the command:
if(LottoNumbers[number] == 1)
{
    // Lotto number is taken.
    return 1;
}
LottoNumbers[number] = 1;

// To reset the lotto numbers use the code below:
for(new i = 0; i < MAX_LOTTO_NUMBERS; i++)
{
    LottoNumbers[i] = 0;
}

Version with bool (Suggested by Kimossab):

pawn Код:

// On top of your gamemode:
#define MAX_LOTTO_NUMBERS 100
new Bool:LottoNumbers[MAX_LOTTO_NUMBERS];

// This goes in the command:
if(LottoNumbers[number] == true)
{
    // Lotto number is taken.
    return 1;
}
LottoNumbers[number] = true;

// To reset the lotto numbers use the code below:
for(new i = 0; i < MAX_LOTTO_NUMBERS; i++)
{
    LottoNumbers[i] = false;
}

Note: "bool" is a weak tag and "Bool" is a strong tag.