Question

1.

What would be the output of the following lines of code:

int num = 2;

switch(num){
    case 1: 
        cout << "1";
    case 2:
        cout << "2";
    case 3:
        cout << "3";
    case 4:
        cout << "4";
}

2.

What would be the output of the following code:

char op = '*';

switch(op){
    case '+': 
        cout << "Addition";
        break;
    case '-':
        cout << "Subtraction";
        break;
    case '/':
        cout << "Division";
        break;
    default:
        cout << "Invalid";
}

3.

What would be the output of the following code:

int num = 2;

switch(num){
    case 1: 
        cout << "1";
        break;
    case 2:
        cout << "2";
    case 3:
        cout << "3";
        break;
    case 4:
        cout << "4";
        break;
}

4.

Give that the file "input.txt" contains the following text:

Quintin Donnelly123

After the following code is executed

ifstream fin;
string firstName = ' ';
string lastName = ' ';
int num = 0;

fin.open("input.txt");
fin >> firstName >> lastName >> num;
fin.close();

What are the values contained in

firstName:

lastName:

num:

5.

Given the file "input.txt" contains the following text:

100 + 20

What would be the output of the following code:

ifstream fin;
int num1, num2;
char op;

fin.open("input.txt");
fin >> num1 >> op >> num2;
fin.close();

switch(op){
    case '+':
        cout << num1+num2;
        break;
    case '-':
        cout << num1-num2;
        break;
    case '*':
        cout << num1*num2;
        break;
    case '/':
        cout << num1/num2;
        break;
    default:
        cout << "Invalid equation.";
}

6.

Given the file "input.txt" contains the following text:

outputMe

Fill in the blank to write to an output file:

#include <iostream>
#include <string>
#include <fstream>

using namespace std;

int main() {
    string data;
    ifstream input("input.txt");
    ofstream output("output.txt");
    // get the input from the file
    input >> data;
    // close the input file
    input.close();
    // write to output file 
    [BLANK] << data;
    // close the ouptutfile
    output.close();
    return 0;
}

Answer 1

Q.1.

Answer : 234

Explanation: Since the value of num=2 so case 2 will match and since break is not used so it will execute all the case blocks starting from 2.

Q2.

Answer : Invalid

Explanatio Since value of op='*' but in switch there is no case block for '*' so it will execute the default block.

Q3.

Answer:23

Explanation:  Since the value of num=2 so case 2 will match and since break is not used so it will execute all the case blocks starting from 2 but in case 3 since break is used so it will terminate the switch block after case -3 will execute.

Q4.

Answer :

Quintin Donnelly123

Explanation : The data from file will be read and store these in firstName,lastName and num so the output will be Quintin Donnelly123

Q5.

Answer :120

Explanation: The data will be read from input.txt and store them in num1,num2and op. So num1 will store 100, op will store + and num2 will store 20

Now op will pass to switch case and case'+' will match so it will execute the block and the result will be 120.

Q6.

Answer :It will show error.
Explanation: input >> data; this statement will read the data from input.txt and store it in data. so the value of data will be outputMe. But the next statement

[BLANK] << data; is invalid because of blank. So it will show error. But if you will replace the blank by output object as output<<data, then it will copy the value of data into output.txt.