View Constraint set Programetically

UIView *redView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 200, 100)];

    redView.backgroundColor = [UIColor redColor];

    redView.translatesAutoresizingMaskIntoConstraints = NO;

    [self.view addSubview:redView];

    // Width

    [redView addConstraint:[NSLayoutConstraint constraintWithItem:redView attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:nil attribute:0 multiplier:1 constant:200]];

    // Height

    [redView addConstraint:[NSLayoutConstraint constraintWithItem:redView attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:nil attribute:0 multiplier:1 constant:100]];

    // X

    [self.view addConstraint:[NSLayoutConstraint constraintWithItem:redView attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeCenterX multiplier:1 constant:0]];

    // Y

    [self.view addConstraint:[NSLayoutConstraint constraintWithItem:redView attribute:NSLayoutAttributeCenterY relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeCenterY multiplier:1 constant:0]];

    [self.view addSubview:redView];