Convert a string into an int

NSString *string = @"5";
int value = [string intValue];

NSString *string = /* Assume this exists. */;
int value = [string intValue];

[@"7" intValue];

[NSNumberFormatter numberFromString:@"7"];

NSInteger stringToInt(NSString *string) {
    return [string integerValue];
}

NSString* intToString(NSInteger integer) {
    return [NSString stringWithFormat:@"%d", integer];
}