Condition statements and looping exercises

1. SJEM2231 STRUCTURED PROGRAMMING
NAME : WAN MOHAMAD FARHAN BIN AB RAHMAN
TUTORIAL 2/ LAB 2 (29TH SEPTEMBER 2014)
(Use different loop structures for problems 4 to 6, and understand how it works)
QUESTION 1
Write a program that asks the user to type the width and length of a rectangle and then print the area and perimeter of the rectangle.
#include <iostream>
using namespace std;
int main ()
{
int width, height, area, perimeter;
cout <<"Please enter width of rectangle:";
cin >> width;
cout <<"Please enter height of rectangle:";
cin >> height;
area=width*height;
perimeter=(2*width)+(2*height); // same as 2*(height+width)
cout << "The area of rectangle is : " << area << endl;
cout << "The perimeter of rectangle is: " << perimeter << endl;
return 0;
}
// Output:
Please enter width of rectangle:10
Please enter height of rectangle:10
The area of rectangle is : 100
The perimeter of rectangle is: 40
QUESTION 2
Write a program that converts inches to centimeters. For example, if the user enters 16.9 for a length in inches, the output would be 42.926 cm.(One inch equals 2.54centimeters)
#include <iostream>
using namespace std;
int main()
{

2. float length_inch, length_cm;
cout << "Please enter length in inches: ";
cin >> length_inch;
length_cm = length_inch*2.54;
cout << "The length in centimeters is : "<< length_cm << endl;
return 0;
}
//Output :
Please enter length in inches: 16.9
The length in centimeters is : 42.926
QUESTION 3
Write a program that reads the user’s age and then prints “You are a child.” if the age < 18, “You are an adult.” if 18 ≤ age < 65, and “You are a senior citizen.” if age ≥ 65.
// Method 1, using do while-loop
#include <iostream> using namespace std; int main() { int age; cout<< "Please enter your age:"; do { cin >> age; if (age < 0) cout << "You have not entered a valid age. Please try again:"; }

3. while(age <= 0);
if (age < 18) cout << "You are a child"<<endl; else if (age>=18 && age<65) cout <<"You are an adult" << endl; else cout<< "You are a senior citizen" << endl; return 0; }
//Output_method1: Please enter your age: -10 You have not entered a valid age. Please try again:22 You are an adult Please enter your age:-2 You have not entered a valid age. Please try again:10 You are a child Please enter your age:-4 You have not entered a valid age. Please try again:81 You are a senior citizen
// Method 2, using if else
#include<iostream> // allows program to perform input and output
using namespace std; // program uses names from the std namespace
int main ()
{
int age;
cout<< "Please enter your age:"; //prompt user for data

4. cin >> age; //read data from user
if (age <0) cout << "Error! You have not entered a valid age" <<endl;
else if (age >= 0 && age < 18)
cout << "You are a child" << endl;
else if (age >= 18 && age < 65)
cout<< "You are an adult" << endl;
else
cout<< "You are a senior citizen" << endl;
return 0;
}
//Output_method2:
Please enter your age:-10 Error! You have not entered a valid age
Please enter your age:14
You are a child
Please enter your age:40
You are an adult
Please enter your age:78
You are a senior citizen
QUESTION 4
Write a program to find the factorial of a given number (N!). // Using the first way of while-loop
#include <iostream>
using namespace std;
int main()

5. {
long double N, factorial;
cout<< "Please enter a number up to 170: ";
cin>> N;
factorial=1;
while ( N > 0)
/* while loop continues until test condition N>0 is true */
{
factorial= factorial*N;
--N;
}
cout<< "Factorial = " << factorial << endl;
return 0;
} //Output :
Please enter a number up to 170: 170
Factorial = 7.25742e+306
//Using the second way of while-loop
#include<iostream>
using namespace std;
int main ()
{
long double n,N, factorial;
cout << "Enter the value of N up to 170 : ";
cin >> N;
cout << endl;

6. factorial = 1;
n= 1;
while(n <= N)
{
factorial= factorial*n;
n= n+1; // or can write as n++
}
cout << "N!= " << factorial << endl;
return 0;
}
//Output:
Enter the value of N up to 170 : 170
N!= 7.25742e+306
// Using for-loop
#include <iostream>
using namespace std;
int main()
{
long double N, int a, factorial=1; /*try use int N */
cout << "Please enter a number up to 170: ";
cin>> N;
if (N< 0)
cout << “Factorial of negative number does not exist n”;

7. else
{
for (a=1; a<=N; a++) //for loop terminates if a > N
{
factorial= factorial*a; //same meaning as factorial*=count
}
cout<< "Factorial of N is equal to " << factorial<< endl;
}
return 0;
}
//Output:
Please enter a number up to 170: 170
Factorial of N is equal to 7.25742e+306
QUESTION 5
Write a program to find the sum of first N natural numbers. (1 + 2 + 3 + 4 + 5 + ⋯+N)
//Using while-loop
#include <iostream>
using namespace std;
int main()
{
int a, N, sum=0;
cout<<"Please enter an integer: ";
cin>> N;
a=1;
while( a <= N) // while loop terminates if a > N
{

8. sum = sum+ a; // also can be write as sum+ = a
a++; // increment a by 1
}
cout<< "Sum = " << sum << endl;
return 0;
}
//Output :
Please enter an integer: 10
Sum = 55
//Using for-loop
#include <iostream>
using namespace std;
int main()
{
int a, N, sum=0;
cout<< "Please enter an integer: " ;
cin>> N;
for(a=1; a<=N; a++) // for loop terminates if a>N
{
sum+= a; // same meaning as sum= sum+a
}
cout<< "Sum = " << sum <<endl ;
return 0;
} //Output :
Please enter an integer: 10
Sum = 55

9. // The program below displays error message when we enters 0 or negative number and displays the sum of natural numbers if we enters positive number
#include <iostream>
using namespace std;
int main()
{
int a, N, sum=0;
cout << "Please enter an integer: " ;
cin >> N;
if (N <= 0)
cout<< "Cannot execute! Error !n" ;
else
{
for(a=1; a <=N; a++) // for loop terminates if a > N
{
sum+= a; // same meaning as sum= sum+a
}
cout<< "Sum = " <<sum<< endl;
}
return 0;
}
//Output:
Please enter an integer: 10
Sum = 55

10. QUESTION 6
Write a program to the sum of a given number of squares. For example, if 5 is input, then the program will print 55, which equals 12+ 22+ 32+ 42+ 52
//Using while-loop
#include <iostream>
using namespace std;
int main()
{
int a, int N, sum=0;
cout<< "Please enter an integer: " ;
cin >> N;
a=1;
while( a <= N) // while loop terminates if a > N
{
sum = sum+ a*a; // also can be write as sum+ = a*a
a++; // same meaning as a=a+1
}
cout << "Sum = " << sum << endl;
return 0;
}
//Output :
Please enter an integer: 5
Sum = 55

11. //Using for-loop
#include <iostream>
using namespace std;
int main()
{
int N, sum=0;
cout<< "Please enter an integer: " ;
cin>> N;
for(int a=1; a<=N; a++) // for loop terminates if a>N
{
sum+= a*a; // same meaning as sum= sum+a*a
}
cout<< "The sum of the squares is equal to " << sum <<endl ;
return 0;
}
//Output:
Please enter an integer: 5
The sum of the squares is equal to 55