using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Office.Core;
using PowerPoint = Microsoft.Office.Interop.PowerPoint;
 
namespace readPPT
{
    class Program
    {
        static void Main(string[] args)
        {
            Microsoft.Office.Interop.PowerPoint.Application PowerPoint_App = new Microsoft.Office.Interop.PowerPoint.Application();
            Microsoft.Office.Interop.PowerPoint.Presentations multi_presentations = PowerPoint_App.Presentations;
            Microsoft.Office.Interop.PowerPoint.Presentation presentation = multi_presentations.Open(@"C:\PPT\myPowerpoint.pptx");
            string presentation_text = "";
            for (int i = 0; i < presentation.Slides.Count; i++)
            {
                foreach (var item in presentation.Slides[i+1].Shapes)
                {
                    var shape = (PowerPoint.Shape)item;
                    if (shape.HasTextFrame == MsoTriState.msoTrue)
                    {
                        if (shape.TextFrame.HasText == MsoTriState.msoTrue)
                        {
                            var textRange = shape.TextFrame.TextRange;
                            var text = textRange.Text;
                            presentation_text += text+" ";
                        }
                    }
                }
            }
            PowerPoint_App.Quit();
            Console.WriteLine(presentation_text);
        }
    }
}