NSString int(long) 変換

NSString -> int

integerValue

NSString *test = @"12";
int val = [test integerValue];

int -> NSString

int val = 12;
NSString *test = [NSString stringWithFormat:@"%d", val];

NSString -> long

NSString *test = @"11111111";
long val = [test longLongValue];

Use longLongValue