for( size_t i = 0; i < faces.size(); i++ ){ Point center( faces[i].x + faces[i].width/2, faces[i].y + faces[i].height/2 );

The for loop in this code snippet iterates through a vector of detected faces (stored in the variable "faces") and calculates the center coordinates for each face.

The loop starts with an index variable "i" initialized to zero, and continues as long as "i" is less than the size of the "faces" vector. The loop increments "i" after each iteration.

Inside the loop, the center coordinates of the current face are calculated using the following formula:

Point center( faces[i].x + faces[i].width/2, faces[i].y + faces[i].height/2 );

The "faces[i].x" and "faces[i].y" variables represent the top-left corner of the current face rectangle, while "faces[i].width" and "faces[i].height" represent the dimensions of the rectangle. The center coordinates are calculated by adding half of the rectangle's width and height to the top-left corner coordinates, respectively.

The resulting center coordinates are stored in a Point object named "center", which can be used for further processing or analysis of the detected faces.