[Misiur]

I've written something for ya:

pawn Code:

stock checker(string[]) {
    new valid = true;
    new patterns[3][] = {
        { "ABCDEFGHIJKLMNOPRSTUWXYZ" },
        { "abcdefghijklmnoprstuwxyz" },
        { "0123456789" }
    };  
    for(new i = 0; i < sizeof(patterns); i++) {
        for(new j = 0; j < strlen(patterns[i]); j++) {
            //This is due to something weird with patterns[i][j]
            new cchar = patterns[i][j]; //We need char
            new sub[2];
            format(sub, sizeof(sub), "%s", cchar); //And string again
            if(-1 != strfind(string, sub)) break; //Found it!
            else {
                //Check if last run, if yes, jump out of here to label
                if(j == (strlen(patterns[i])-1)) {
                    valid = false;
                    goto finish_now;
                }
            }
        }
    }
    finish_now:
    return valid;
}

You can change patterns to some other if you want

Example usage:

pawn Code:

new str[5];
str = ((checker("I like 9 pancakes")) ? ("Yup") : ("Nope"));
printf("%s", str);
str = ((checker("I like pancakes")) ? ("Yup") : ("Nope"));
printf("%s", str);
str = ((checker("i like pancakes")) ? ("Yup") : ("Nope"));
printf("%s", str);

Result: Yup, Nope, Nope

(Goto only for sake of getting out of double loop without additional variables)