Making curved lines on a line graph

Hello.

Using several sources on-line, I have created a method to draw a line graph:

float data[] = {0.7, 0.4, 0.9, 1.0, 0.2, 0.85, 0.11, 0.75, 0.53, 0.44, 0.88, 0.77, 0.99, 0.55};

- (void)drawLineGraphWithContext:(CGContextRef)ctx
{
    CGContextSetLineWidth(ctx, 2.0);
    CGContextSetStrokeColorWithColor(ctx, [[UIColor colorWithRed:1.0 green:0.5 blue:0 alpha:1.0] CGColor]);
  
    int maxGraphHeight = kGraphHeight - kOffsetY;
  
    CGGradientRef gradient;
    CGColorSpaceRef colorspace;
    size_t num_locations = 2;
    CGFloat locations[2] = {0.0, 1.0};
    CGFloat components[8] =
    {   0.0, 0.0, 204/255, 0.2,     /
        51/255, 153/255, 0.0, 1.0      /
    };
  
    colorspace = CGColorSpaceCreateDeviceRGB();
    gradient = CGGradientCreateWithColorComponents(colorspace, components, locations, num_locations);
  
    CGPoint startPoint, endPoint;
    startPoint.x = kOffsetX;
    startPoint.y = kGraphHeight;
    endPoint.x = kOffsetX;
    endPoint.y = kOffsetY;
  
    CGContextAddLineToPoint(ctx, kOffsetX + (sizeof(data) - 1) * kStepX, kGraphHeight);
    CGContextClosePath(ctx);
  
    CGContextSetFillColorWithColor(ctx, [[UIColor colorWithRed:1.0 green:0.5 blue:0 alpha:0.5] CGColor]);
  
    CGContextBeginPath(ctx);
    CGContextMoveToPoint(ctx, kOffsetX, kGraphHeight);
  
    CGContextAddLineToPoint(ctx, kOffsetX, kGraphHeight - maxGraphHeight * data[0]);
    for (int i = 1; i < sizeof(data); i++)
    {
        CGContextAddLineToPoint(ctx, kOffsetX + i * kStepX, kGraphHeight - maxGraphHeight * data[i]);
      
    }
    CGContextAddLineToPoint(ctx, kOffsetX + (sizeof(data) - 1) * kStepX, kGraphHeight);
    CGContextClosePath(ctx);
  
    CGContextSaveGState(ctx);
    CGContextClip(ctx);
    CGContextDrawLinearGradient(ctx, gradient, startPoint, endPoint, 0);
  
    CGContextRestoreGState(ctx);
    CGColorSpaceRelease(colorspace);
    CGGradientRelease(gradient);
}

What I want to do now is to have curved lines on the graph. Tried to use CGContextAddQuadCurveToPoint in the for-loop but do not get the intended results. Is this the way to go?

Thank you!