chap 2

Question 1

What are pre processor directives?
what are eg of directives ?
what is a header file?

Answer 1

define – Define Macros

Preprocessor Directives are instructions that are processed before compilation. it prepares/ready the code for compilation. for eg. #define PI 3.1415 here here at every occurrence of Pi will be replaced by 3.14

After this directive is processed by the preprocessor, every occurrence of PI in the code will be replaced by 3.1415.
The replacement happens before the compiler even looks at the code.

#include – File Inclusion
#ifdef / #ifndef – Check if a Macro is Defined

A header file is a file with a .h extension that contains declarations of functions, classes, and macros. The actual implementations (definitions) of these functions and classes are typically found in a corresponding .cpp file.

Question 2

use ternary operator to find if the value is even or odd

Answer 2

// Online C++ compiler to run C++ program online
#include <iostream>
using namespace std;</iostream>

int main() {
bool flag = true;
(flag == true )? cout&laquo_space;“yes” : cout&laquo_space;“no!”;
int max ;
int a = 2 ;
int b = 3;
(a>b) ? max = a : max =b;
cout &laquo_space;“max = “ &laquo_space;max;

return 0; }

Question 3

Write a program to print pyramid of numbers using nested for loop

Answer 3

include <iostream></iostream>

using namespace std;

int main() {
int i, j, k;
int num = 5;

for (i = 1; i <= num; i++) {
    // Print spaces
    for (k = 1; k <= num - i; k++) {
        cout << " ";
    }

    // Print numbers
    for (j = 1; j <= i; j++) {
        cout << j;
    }

    cout << "\n";
}

return 0; }

Question 4

datatypes in cpp

Answer 4

3 types built in , derived and user defined
built in : char, int, float, void
derived datatypes:
array, functions, pointers, references
user defended datatype:
structure, union, class, enum

Question 5

size of char int float double long double

Answer 5

1,2,4,8,10

Question 6

how will you use enum

Answer 6

enum weekdays{SUN, MON, TUE, WED, THUR, FRI, SAT}
Enumerators are use to attach numbers to names,

Question 7

what is typedef?

Answer 7

typedef is used to change the name of datatype eg:
typedef int whole;
now insted of int we can write whole
whole sum = 2 ;

Question 8

type conversion

Answer 8

automatic :compiler converts data type to larger datatype

typecasting: programmer convert one data type to another datatype
by mentioning the type explicitly
int sum;
average = float(sum) /5;

Question 9

variable

Answer 9

is name given to some part of memory location

Question 10

rvalue , lvalue

Answer 10

the value which is assigned
the var that is to be assigned

Question 11

const (literals)

Answer 11

values cannot be changed onced assigned

Question 12

operators in cpp

Answer 12

arithmatic
relational
logical operators
bitwize operators
special operators
escape sequence

Question 13

difference between preincrement and post increment

Answer 13

i++ and ++i

Question 14

Control statement

Answer 14

selection : if , if-else, switch, nested if

iterative looping : for, while, do-while, nested for

breaking : break, continue, goto exit

Question 15

check if the no. is odd or even

Answer 15

include<iostream></iostream>

using namespace std;

int main(){
int value = 3;
if (value%2==0){
cout«“odd”;}
else{
cout«“even”;
}
}

Question 16

menu driven program to cal the are of circle rectangle and triangle

Answer 16

include <iostream></iostream>

using namespace std;
#define PI 3.1415

int main() {
int option;
int base, height, r, length;

cout << "Select proper option from the following:\n";
cout << "Press 1 to find area of circle\n";
cout << "Press 2 to find area of square\n";
cout << "Press 3 to find area of triangle\n";
cin >> option;

switch (option) {
    case 1:
        cout << "Enter radius: ";
        cin >> r;
        float areaOfCircle = PI * r * r;
        cout << "The area of Circle is: " << areaOfCircle << endl;
        break;

    case 2:
        cout << "Enter length: ";
        cin >> length;
        float areaOfSquare = length * length;
        cout << "The area of Square is: " << areaOfSquare << endl;
        break;

    case 3:
        cout << "Enter base: ";
        cin >> base;
        cout << "Enter height: ";
        cin >> height;
        float areaOfTriangle = 0.5 * base * height;
        cout << "The area of Triangle is: " << areaOfTriangle << endl;
        break;

    default:
        cout << "Enter a proper value." << endl;
        break;
}

return 0; }

Question 17

program to find factorial

Answer 17

//Find factorial of a given number
#include <iostream>
using namespace std;
int main(){
int factorial = 1;
int number;
int i = 0;
cout<<"Enter a no.";
cin >> number;</iostream>

for(i=1; i<=number; i++){
    factorial = factorial * i;
}
cout << factorial << " is the factorial of "<<number;
return 0;

}

Question 18

program to print pyramid
1
12
123
1234
12345

Answer 18

include <iostream></iostream>

0
01
012
0123
01234
012345

using namespace std;
int main(){
int i = 0;
int n = 5;
int j = 0;
for(i=0; i<=n ; i++){
for(j=0; j<=i;j++){
cout«j;
}
cout«“\n”;
}
}

========
code: #include <iostream>
using namespace std;
int main(){
int i = 0;
int n = 5;
int j = 0;
int k = 0;
for(i=1; i<=n ; i++){
for(k=1;k<=n-i;k++){
cout<<" ";
}
for(j=1; j<=i;j++){
cout<<j;
}
cout<<"\n";
}
}
=======
1234
123
12
1
#include <iostream>
using namespace std;
int main(){
int i = 0;
int n = 5;
int j = 0;
int k = 0;
for(i=1; i<=n ; i++){
for(k=1;k<=n-i;k++){
cout<<k;
}
cout<<"\n";
}
}</iostream></iostream>

Question 19

to check if the number is palindrome

Answer 19

include<iostream></iostream>

//to check if the number is palindrome or not?

using namespace std;
int main(){
int originalNo = 0;
int changedNo = 0;
int revNo = 0;
int unitDigit = 1;
cout«“Enter Original Number”;
cin»originalNo;
changedNo = originalNo;
do{
unitDigit = changedNo % 10;
revNo = revNo * 10 + unitDigit;
changedNo = changedNo/10;
}
while(changedNo>0);
if(revNo == originalNo){
cout&laquo_space;originalNo «” is palindrome no.”;
}
else{
cout«originalNo«” is Not a palindrome”;
}
return 0;
}

Question 20

what is the difference between while loop and do while loop?

Answer 20

While loop is used when we do not know the fixed no. of iteration. here first initial condition is checked if is true then enters the while loop while is entry controlled loop.

in do while loop the body is executed at least once and then the condition is checked it is also called as exit controlled loop.

Question 21

program to demonstrate
1.break
2.goto
3.continue
4.exit

Answer 21

break is used to break the iteration
goto is used to goto that label
continue is opposite of break , it continues the iteration
exit: exit will exit() the program (we need to include process or stdlib)

Question 22

Write a program to print pyramid of numbers using nested for loop

Answer 22

include <iostream></iostream>

using namespace std;

int main() {
int i, j, k;
int num = 5;

for (i = 1; i <= num; i++) {
    // Print spaces
    for (k = 1; k <= num - i; k++) {
        cout << " ";
    }

    // Print numbers
    for (j = 1; j <= i; j++) {
        cout << j;
    }

    cout << "\n";
}

return 0; }

Question 23

program to find the simple interest

Answer 23

include<iostream></iostream>

using namespace std;
int main(){
float principal, rate, time, si;
cout«“Enter Principal, rate, time”;
cin»principal»rate»time;

si = (principal*rate*time)/100;
cout<<si<<" is the simple intrest.";

}

Question 24

from Q3 onwards