The introductory sample program for Opencv in Visual Studio exits with code -1. No reasion

Question

I have installed Visual Studio 15.5.3

I have installed OpenCV 3.4.0

I am trying to get this example OpenCV program to run.

#include “stdafx.h”
#include <opencv2/highgui/highgui.hpp>
#include <iostream>
using namespace cv;
using namespace std;
int main(){ 
Mat im = imread("c:/full/path/to/lena.jpg"); 
if (im.empty()){ 
cout << "Cannot load image!" << endl; return -1; 
} 
imshow("Image", im);
waitKey(0); 
}

I have inserted the example code into the default Visual Studio C++ template as follows:

 // Open Computer Vision Program.cpp : Defines the entry point for the application.
    //

    #include "stdafx.h"
    #include "Open Computer Vision Program.h"

    ////    Example Code
    #include <opencv2/highgui/highgui.hpp>
    #include <iostream>
    using namespace cv;
    using namespace std;
   ////    Example Code


    #define MAX_LOADSTRING 100

    // Global Variables:
    HINSTANCE hInst;                                // current instance
    WCHAR szTitle[MAX_LOADSTRING];                  // The title bar text
    WCHAR szWindowClass[MAX_LOADSTRING];            // the main window class name

    // Forward declarations of functions included in this code module:
    ATOM                MyRegisterClass(HINSTANCE hInstance);
    BOOL                InitInstance(HINSTANCE, int);
    LRESULT CALLBACK    WndProc(HWND, UINT, WPARAM, LPARAM);
    INT_PTR CALLBACK    About(HWND, UINT, WPARAM, LPARAM);

    int APIENTRY wWinMain(_In_ HINSTANCE hInstance,
                         _In_opt_ HINSTANCE hPrevInstance,
                         _In_ LPWSTR    lpCmdLine,
                         _In_ int       nCmdShow)
    {
        UNREFERENCED_PARAMETER(hPrevInstance);
        UNREFERENCED_PARAMETER(lpCmdLine);

        // TODO: Place code here.

        ////    Example Code
        Mat im = imread("c:lena.jpg");
        if (im.empty())
        {
            cout << "Cannot load image!" << endl;
            return -1;
        }
        imshow("Image", im);
        waitKey(0);
        ////    Example Code

        // Initialize global strings
        LoadStringW(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
        LoadStringW(hInstance, IDC_OPENCOMPUTERVISIONPROGRAM, szWindowClass, MAX_LOADSTRING);
        MyRegisterClass(hInstance);

        // Perform application initialization:
        if (!InitInstance (hInstance, nCmdShow))
        {
            return FALSE;
        }

        HACCEL hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_OPENCOMPUTERVISIONPROGRAM));

        MSG msg;

        // Main message loop:
        while (GetMessage(&msg, nullptr, 0, 0))
        {
            if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
            {
                TranslateMessage(&msg);
                DispatchMessage(&msg);
            }
        }

        return (int) msg.wParam;
    }



    //
    //  FUNCTION: MyRegisterClass()
    //
    //  PURPOSE: Registers the window class.
    //
    ATOM MyRegisterClass(HINSTANCE hInstance)
    {
        WNDCLASSEXW wcex;

        wcex.cbSize = sizeof(WNDCLASSEX);

        wcex.style          = CS_HREDRAW | CS_VREDRAW;
        wcex.lpfnWndProc    = WndProc;
        wcex.cbClsExtra     = 0;
        wcex.cbWndExtra     = 0;
        wcex.hInstance      = hInstance;
        wcex.hIcon          = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_OPENCOMPUTERVISIONPROGRAM));
        wcex.hCursor        = LoadCursor(nullptr, IDC_ARROW);
        wcex.hbrBackground  = (HBRUSH)(COLOR_WINDOW+1);
        wcex.lpszMenuName   = MAKEINTRESOURCEW(IDC_OPENCOMPUTERVISIONPROGRAM);
        wcex.lpszClassName  = szWindowClass;
        wcex.hIconSm        = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));

        return RegisterClassExW(&wcex);
    }

    //
    //   FUNCTION: InitInstance(HINSTANCE, int)
    //
    //   PURPOSE: Saves instance handle and creates main window
    //
    //   COMMENTS:
    //
    //        In this function, we save the instance handle in a global variable and
    //        create and display the main program window.
    //
    BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
    {
       hInst = hInstance; // Store instance handle in our global variable

       HWND hWnd = CreateWindowW(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
          CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, nullptr, nullptr, hInstance, nullptr);

       if (!hWnd)
       {
          return FALSE;
       }

       ShowWindow(hWnd, nCmdShow);
       UpdateWindow(hWnd);

       return TRUE;
    }

    //
    //  FUNCTION: WndProc(HWND, UINT, WPARAM, LPARAM)
    //
    //  PURPOSE:  Processes messages for the main window.
    //
    //  WM_COMMAND  - process the application menu
    //  WM_PAINT    - Paint the main window
    //  WM_DESTROY  - post a quit message and return
    //
    //
    LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
    {
        switch (message)
        {
        case WM_COMMAND:
            {
                int wmId = LOWORD(wParam);
                // Parse the menu selections:
                switch (wmId)
                {
                case IDM_ABOUT:
                    DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
                    break;
                case IDM_EXIT:
                    DestroyWindow(hWnd);
                    break;
                default:
                    return DefWindowProc(hWnd, message, wParam, lParam);
                }
            }
            break;
        case WM_PAINT:
            {
                PAINTSTRUCT ps;
                HDC hdc = BeginPaint(hWnd, &ps);
                // TODO: Add any drawing code that uses hdc here...
                EndPaint(hWnd, &ps);
            }
            break;
        case WM_DESTROY:
            PostQuitMessage(0);
            break;
        default:
            return DefWindowProc(hWnd, message, wParam, lParam);
        }
        return 0;
    }

    // Message handler for about box.
    INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
    {
        UNREFERENCED_PARAMETER(lParam);
        switch (message)
        {
        case WM_INITDIALOG:
            return (INT_PTR)TRUE;

        case WM_COMMAND:
            if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
            {
                EndDialog(hDlg, LOWORD(wParam));
                return (INT_PTR)TRUE;
            }
            break;
        }
        return (INT_PTR)FALSE;
    }

The code runs with no compile errors and no debug errors. But, the program does not do anything and exits with a code of -1.

I have corrected all of the installation and compile errors, but something is still wrong and I do not see it.

Does anyone have an idea?

Answer 1

Your filepath is wrong

Mat im = imread("c:lena.jpg");

You probably need some slashes, I would suggest double backslash

Mat im = imread("c:\\lena.jpg");

This means OpenCV Can't find the image and returns with -1 on these lines

 if (im.empty())
    {
        cout << "Cannot load image!" << endl;
        return -1;
    }

The reason you don't see the console out is probably because the console closes straight after returning, although that's a guess.