main function and program entry in C++ - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define the main function that returns 0.

C++

int [1]() {
    return 0;
}

Drag options to blanks, or click blank then click option'

Abegin

Bstart

Cmain

Drun

Attempts:

3 left

💡 Hint

Common Mistakes

Using a function name other than 'main' for the program entry point.

Forgetting to define the main function.

The main function is the entry point of a C++ program. It must be named main.

2fill in blank

medium

Complete the code to print "Hello, World!" inside the main function.

C++

#include <iostream>

int main() {
    std::[1] << "Hello, World!" << std::endl;
    return 0;
}

Drag options to blanks, or click blank then click option'

Acout

Bprint

Cwrite

Doutput

Attempts:

3 left

💡 Hint

Common Mistakes

Using print instead of cout in C++.

Forgetting to use std:: prefix or using namespace std;.

In C++, std::cout is used to print output to the console.

3fill in blank

hard

Fix the error in the main function declaration to make it valid.

C++

int [1](int argc, char* argv[]) {
    return 0;
}

Drag options to blanks, or click blank then click option'

Astart

Bprogram

Centry

Dmain

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different function name instead of main.

Incorrect function signature for the program entry point.

The correct name for the program entry function with arguments is main.

4fill in blank

hard

Fill both blanks to complete the main function that prints the first command line argument.

C++

#include <iostream>

int [1](int argc, char* argv[]) {
    if (argc > 1) {
        std::cout << argv[[2]] << std::endl;
    }
    return 0;
}

Drag options to blanks, or click blank then click option'

Amain

B0

C1

Dstart

Attempts:

3 left

💡 Hint

Common Mistakes

Using argv[0] which is the program name, not the first argument.

Using a wrong function name for the entry point.

The main function is named main. The first command line argument is at argv[1] because argv[0] is the program name.

5fill in blank

hard

Fill all three blanks to complete a main function that prints all command line arguments except the program name.

C++

#include <iostream>

int [1](int argc, char* argv[]) {
    for (int i = [2]; i < argc; ++i) {
        std::cout << argv[[3]] << std::endl;
    }
    return 0;
}

Drag options to blanks, or click blank then click option'

Amain

B0

Ci

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Starting loop from 0 which prints the program name.

Using a fixed index inside the loop instead of the loop variable.

The main function is named main. The loop starts at 1 to skip the program name. Inside the loop, argv[i] accesses each argument.