c++ what is %

cv2.imshow("frame",frame) cv2.error: opencv(4.4.0) c:\users\appveyor\appdata\local\temp\1\pip-req-build-wwma2wne\opencv\modules\highgui\src\window.cpp:376: error: (-215:assertion failed) size.width>0

Fatal error: Composer detected issues in your platform: Your Composer dependencies require a PHP version ">= 7.3.0". You are running 7.2.19. in C:\php\largon\laragon\www\medmazza-simple-master\vendor\composer\platform_check.php on line 24

he current Numpy installation ('C:\\Users\\muham\\.virtualenvs\\Backend-vjttHJMD\\lib\\site-packages\\numpy\\__init__.py') fails to pass a sanity check due to a bug in the windows runtime. See this issue for more information: https://tinyurl.com/y3dm3h86

Write a c code to create a data base of students using structure. The member variables are roll, grade, and marks. Create 3 structure variable of 3 different roll numbers and find out the roll number of the student who is having highest marks.

[ WARN:0] global C:\Users\appveyor\AppData\Local\Temp\1\pip-req-build-wwma2wne\o pencv\modules\videoio\src\cap_msmf.cpp (677) CvCapture_MSMF::initStream Failed t o set mediaType (stream 0, (640x480 @ 30) MFVideoFormat_RGB24(codec not found)