Consider the following program segment.
Ifstream inFile; //Line 1
Int x,y; //Line 2
... //Line 3
InFile x y; //Line 4
Which of the following statements at Line 3 can be used to open the file progdata.dat and input data from this file into x and y at Line 4?
A) inFile.open("progdata.dat");
B) inFile(open,"progdata.dat");
C) open.inFile("progdata.dat");
D) open(inFile,"progdata.dat");

Question

Consider the following program segment.
Ifstream inFile; //Line 1
Int x,y; //Line 2
... //Line 3
InFile >> x >> y; //Line 4
Which of the following statements at Line 3 can be used to open the file progdata.dat and input data from this file into x and y at Line 4?
A) inFile.open("progdata.dat");
B) inFile(open,"progdata.dat");
C) open.inFile("progdata.dat");
D) open(inFile,"progdata.dat");

Quizplus · Accepted Answer

Option A is the correct way to open the file progdata.dat and input data from this file into x and y. The ifstream object inFile is initialized with the file name using the open method. It takes the file name as a parameter and opens the file for input operations. So, in line 4, when we use the extraction operator (>>) to extract values from the file into variables x and y, it will work seamlessly. 
Option B is incorrect, as the parentheses syntax is not correct in this expression. 
Option C is incorrect because the method syntax is wrong. This is not a member function of the stream class, this syntax is similar to accessing members of an object, whereas ifstream doesn't have a member function named open. 
Option D is incorrect because it uses some reverse syntax. The open method is expected to be called on the inFile object, and the filename is passed as a parameter.

Consider the Following Program Segment