quick question something about array..

when i put name[30].. what it actually means?the 30.. izzit i can have 31 character inside it?.. if so when i type name like name: john ian something then the then row which matrix needed 2 be key in will be skipped..

EG normal case:
Name: John
Matrix: bk110110
sex: Male

ABnormal case:
Name: John ian ian
Matrix: Sex:Male

i cant key in the matrix