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FP 201 PROGRAMMING FUNDAMENTAL

LAB 2: OPERATORS AND EXPRESSION

Learning Outcome:

By the end of this lab, students should be able to:

Understand operators, operator’s precedence and expression.

Theory/ Topics

A simple C++ program is similar to a C program. In C++ programs the statements to be executed are contained inside the function.

In operators and expressions, student must know about:a)Arithmetic operators ( +, -, *, /, % ) The five arithmetical operations supported by the C++ language are:

+ addition- subtraction* multiplication/ division% modulus

b)Compound assignment (+=, -=, *=, /=, %=, >>=, <<=, &=, ^=, |=)

c)Increment and decrement (++, --)Shortening even more some expressions, the increase operator (++) and the decrease operator (--) increase or reduce by one the value stored in a variable. They are equivalent to +=1 and to -=1, respectively.

Example 1 Example 2B=3;A=++B;// A contains 4, B contains 4

B=3;A=B++;// A contains 3, B contains 4

d) Relational and equality operators (==, !=, >, <, >=, <= )In order to evaluate a comparison between two expressions we can use the relational and equality operators. The result of a relational operation is a Boolean value that can only be true or false, according to its Boolean result.

e) Logical operators ( !, &&, || )The Operator ! is the C++ operator to perform the Boolean operation NOT, it has only one operand, located at its right, and the only thing that it does is to inverse the value of it, producing false if its operand is true and true if its operand is false. Basically, it returns the opposite Boolean value of evaluating its operand.

Precedence of operatorsWhen writing complex expressions with several operands, we must follow the precedence which is what operand is evaluated first and which later. For example, in this expression:

a = 5 + 7 % 2

7%2 is evaluated first, then followed by operator +


Activity 2A

Procedure :

Step 1: Type the programs given belowStep 2: Compile and run the program. Write the output.Step 3: Save the program as Lab2A.cpp.

#include <iostream>using namespace std;int main(){int class1 = 100;int class2 = 200;int class3 = 300;int class4 = 400;int class5 = 500;int sum = 0;

double average;sum = class1 + class2 + class3 + class4 + class5;average = sum/5;cout << " Sum = " << sum << endl;cout << " Average = " << average << endl;return 0;}

Activity 2B

Procedure :

Step 1: Type the programs given belowStep 2: Compile and run the program. Write the output.Step 3: Save the program as Lab2B.cpp.

#include <iostream>using namespace std;

void main(){

int x = 180, y = 200;y = x++;cout << " x : " << x << endl << " y : " << y << endl;

}

Activity 2C

Procedure :

Step 1: Type the programs given belowStep 2: Compile and run the program. Write the output.Step 3: Save the program as Lab2C.cpp.



void main(){

int x = 180, y = 200;y = ++ x;cout << " x : " << x << endl << " y : "<< y << endl;

}

Activity 2D

Procedure :

Step 1: Type the programs given belowStep 2: Compile and run the program. Write the output.Step 3: Save the program as Lab2D.cpp.


void main(){

double p = 12.5;double q = 3.234;p *= q - 1;q += p + 1;cout << " p is " << p << endl << " q is " << q << "\n";

}

Lab 2E

Procedure :

Step 1: Type the programs given belowStep 2: Compile and run the program. Write the output.Step 3: Save the program as Lab2E.cpp.

// Demonstrate the modulus operator. #include <iostream> using namespace std; int main() { int x, y; x = 10; y = 3; cout << x << " / " << y << " is " << x / y << " with a remainder of " << x % y << "\n";

x = 1; y = 2; cout << x << " / " << y << " is " << x / y << "\n" << x << " % " << y << " is " << x % y; return 0; }


Lab 2F

Procedure :

Step 1: Type the programs given belowStep 2: Compile and run the program. Write the output.Step 3: Save the program as Lab2F.cpp.

// Demonstrate the relational and logical operators. #include <iostream> using namespace std; int main() { int i, j; bool b1, b2; i = 10; j = 11; if(i < j) cout << "i < j\n"; if(i <= j) cout << "i <= j\n";if(i != j) cout << "i != j\n"; if(i == j) cout << "this won't execute\n"; if(i >= j) cout << "this won't execute\n"; if(i > j) cout << "this won't execute\n";

b1 = true; b2 = false; if(b1 && b2) cout << "this won't execute\n"; if(!(b1 && b2)) cout << "!(b1 && b2) is true\n"; if(b1 || b2) cout << "b1 || b2 is true\n"; return 0; }

Lab 2G

Procedure :

Step 1: Type the programs given belowStep 2: Compile and run the program. Write the output.Step 3: Save the program as Lab2G.cpp.

#include<iostream>using namespace std;

void main(){

int i;for(i=1;i<=10;i++)cout<<i<<" /2 is: " << (float) i/2 << "\n";

}


LAB EXERCISE

1. Write the C++ expression for the following mathematical statement

a. y=(x-2)(x+3)b. min = a + b + c + d + e

5 (2 marks)

2. Given the values x=5, y=5 and c=3. Write a program to calculate the value of z and display the output of z

z = xy % c + 10 / 2y + 5; (4 marks)

3. Based on the flowchart, find the values for a and b. Write a program to calculate the values and display the output (4 marks)

CONCLUSION

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start

x=12, y=8,z=5

a=x*y-z

b = (6*a/2+3-z)/2

print a,b

end

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