Function

if(IsValidText("Hi there")) return SendClientMessage(playerid, 0xFF0000FF, "Valid Text"); // Correct
if(IsValidText(":> Hello There")) return SendClientMessage(playerid, 0xFF0000FF, "Invailid Text"); // Correct
if(IsValidText("Hello :> There")) return SendClientMessage(playerid, 0xFF0000FF, "Vailid Text"); // Wrong

stock IsValidText(text[])
{
    for(new i = 0; i < sizeof(text[]); i++)
    {
        if(text[i] == 'a' || text[i] == 'b' || text[i] == 'c' || text[i] == 'd'
        || text[i] == 'e' || text[i] == 'f' || text[i] == 'g' || text[i] == 'h'
        || text[i] == 'i' || text[i] == 'j' || text[i] == 'k' || text[i] == 'l'
        || text[i] == 'm' || text[i] == 'n' || text[i] == 'o' || text[i] == 'p'
        || text[i] == 'q' || text[i] == 'r' || text[i] == 's' || text[i] == 't'
        || text[i] == 'u' || text[i] == 'v' || text[i] == 'w' || text[i] == 'x'
        || text[i] == 'y' || text[i] == 'z')
        return 1;
    }
    return 0;
}

[Sascha]

for(new i = 0; i < sizeof(text); i++)

however I guess that's not the actual problem

[MadeMan]

stock IsValidText(text[])
{
    for(new i = 0; text[i]; i++)
    {
        if(text[i] != 'a' && text[i] != 'b' && text[i] != 'c' && text[i] != 'd'
        && text[i] != 'e' && text[i] != 'f' && text[i] != 'g' && text[i] != 'h'
        && text[i] != 'i' && text[i] != 'j' && text[i] != 'k' && text[i] != 'l'
        && text[i] != 'm' && text[i] != 'n' && text[i] != 'o' && text[i] != 'p'
        && text[i] != 'q' && text[i] != 'r' && text[i] != 's' && text[i] != 't'
        && text[i] != 'u' && text[i] != 'v' && text[i] != 'w' && text[i] != 'x'
        && text[i] != 'y' && text[i] != 'z')
        return 0;
    }
    return 1;
}

[Sascha]

won't that be an endless loop?

[Vince]

stock IsValidText(const text[])
{
    for(new i = 0; i < sizeof(text); i++)
        if(!('A' <= text[i] <= 'Z') && !('a' <= text[i] <= 'z')) return 0;

    return 1;
}

ASCII table: http://www.asciitable.com/index/asciifull.gif

indeterminate array size in "sizeof" expression (symbol "")

if i change

for(new i = 0; i < sizeof(text); i++)

to

for(new i = 0; i < sizeof(text[]); i++)

i will repove the warning but i will get save bug at my 1 post

[Vince]

Sorry, this one should work. Tested it.

IsValidText(const text[])
{
    for(new i = 0, j = strlen(text); i < j; i++)
        if(!('A' <= text[i] <= 'Z') && !('a' <= text[i] <= 'z')) return 0;

    return 1;
}

[MadeMan]

Originally Posted by Sascha

won't that be an endless loop?

No, it will stop when reached to the end of the string.

Doing

for(new i = 0; text[i]; i++)

is same as

for(new i = 0; text[i] != 0; i++)

same as

for(new i = 0; text[i] != EOS; i++)

same as

for(new i = 0; text[i] != '\0'; i++)