在NSMutableArray中存储动态数据时出现问题?

结构TCo坐标 浮点数x; 浮动y; . 然后在drawRect方法中,我生成了一个类似的结构对象。

struct TCo_ordinates *tCoordianates; 

现在我画Y轴的图形,代码是。

    fltX1 = 30;
fltY1 = 5;
fltX2 = fltX1;
fltY2 = 270;
CGContextMoveToPoint(ctx, fltX1, fltY1);
CGContextAddLineToPoint(ctx, fltX2, fltY2);
NSArray *hoursInDays = [[NSArray alloc] initWithObjects:@"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",@"9",@"10",@"11",@"12", nil];
for(int intIndex = 0  ; intIndex < [hoursInDays count] ; fltY2-=20, intIndex++)
{   
    CGContextSetRGBStrokeColor(ctx, 2, 2, 2, 1); 
    //CGContextSetRGBStrokeColor(ctx, 1.0f/255.0f, 1.0f/255.0f, 1.0f/255.0f, 1.0f);   
    CGContextMoveToPoint(ctx, fltX1-3 , fltY2-40);
    CGContextAddLineToPoint(ctx, fltX1+3, fltY2-40);
    CGContextSelectFont(ctx, "Helvetica", 14.0, kCGEncodingMacRoman);
    CGContextSetTextDrawingMode(ctx, kCGTextFill);
    CGContextSetRGBFillColor(ctx, 0, 255, 255, 1);
    CGAffineTransform xform = CGAffineTransformMake(
                                                    1.0,  0.0,
                                                    0.0, -1.0,
                                                    0.0,  0.0);
    CGContextSetTextMatrix(ctx, xform);
    const char *arrayDataForYAxis = [[hoursInDays objectAtIndex:intIndex] UTF8String];
    float x1 = fltX1-23;
    float y1 = fltY2-37;
    CGContextShowTextAtPoint(ctx, x1, y1, arrayDataForYAxis, strlen(arrayDataForYAxis));
    CGContextStrokePath(ctx);

现在我想动态地将生成的x1和y1的值存储在NSMutableArray中,因为我编写了代码。

NSMutableArray *yAxisCoordinates = [[NSMutableArray alloc] autorelease];
    for(int yObject = 0; yObject < intIndex; yObject++)
    {
        [yAxisCoordinates insertObject:(tCoordianates->x = x1,tCoordianates->y = y1) atIndex:yObject];  

    }

以上代码正确?????????????