How to display a single frame from a webcam stream with the press of a key? It's showing assertion failed when I tried to compile the code.

edit

You are mixing up C and C++ code interfaces. Could you try this piece of code? Also many systems require you to and the output of the waitKey command with 0xFF.

   #include "opencv2/highgui/highgui.hpp" 
   #include <iostream> 
   #include "opencv2/opencv.hpp" 

   using namespace cv; 
   using namespace std; 

   int main(int, char**) 
   { 
        VideoCapture capturo(0); 
        Mat img1, img2; 
        int input; 
        namedWindow("Image 1",CV_WINDOW_AUTOSIZE); 
        namedWindow("Image 2",CV_WINDOW_AUTOSIZE); 
        for(;;){ 
             int input = 0xFF & waitKey(33);
             if(input == 27) break;
             if (input == 49){ 
                  capturo >> img1;
                  imshow("Image 1",img1.clone()); 
             }
             if (input == 50){ 
                   capturo >> img2;
                   imshow("Image 2",img2.clone()); 
             }
        } 
  return 0; 
  }