mplement the function fileSum. fileSum is passed in a name of a file. This function should open the file, sum all of the integers within this file, close the file, and then return the sum. If the file does not exist, this function should output an error message and then call the exit function to exit the program with an error value of 1.Please Use This Code Template To Answer the Question#include #include #include //needed for exit functionusing namespace std;// Place fileSum prototype (declaration) hereint main() {string filename;cout << "Enter the name of the input file: ";cin >> filename;cout << "Sum: " << fileSum(filename) << endl;return 0;}// Place fileSum implementation here

Which of the following is a difference between the systems development life cycle (sdlc) and extreme programming (xp)? the sdlc model has a separate planning and analysis phase, whereas xp combines both the phases into one phase.in the sdlc model, changes cannot be made to a system once it is delivered to the user, whereas the xp method delivers the system to the users and then make changes suggested by the user.the sdlc model develops an entire system at once, whereas xp uses incremental steps to improve an information system's qualitydevelopers following the sdlc model cannot go on to the next phase until the current phase is finished, whereas in xp, developers can move to any phase from the current phase.