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- 1. F P 201 - PROGRAMMING FUNDAMENTAL LAB 1: VARIABLE, KEYWORD AND DATA TYPES Objectives By the end of this lab, students should be able to : • Describe the structure of C++ programmes • Write, compile and run simple C++ programmes • Identify and list keywords • List and define the various data types • Define variables and constants Theory/ Topics • A program must have the function named main(). • Structure of C++ programmes o The structure of a simple C++ programme is similar to the structure of C. Structure Program < Comment Entry> // First C++ program < Preprocessor directives > #include <iostream> #include <string> main function int main() { { < declaration stat >; int a; < C++ Statements >; cout << "Welcome to } Programming n”; return 0; } Table 1.1 : Structure of C++ Programme 1
- 2. F P 201 - PROGRAMMING FUNDAMENTAL Consider the code in the given program: 1. // is used to comment a single line. In addition to // symbol, C++ supports /* */ for comment entry operation. /* */ is used to comment a set of statements. 2. #include <iostream> includes the header file for the program. 3. main() is the function where the program is written. 4. int a; is the variable declaration. 5. cout is used to display the output statements. 6. Every statement is terminated with a semi-colon, similar to C. • Keywords - have a strict meaning as individual tokens in C++. They cannot be redefined or used in other contexts. • Identifier - Sequence of letters, digits and the special character "_" which is called an underscore. A letter or underscore must be the first character of an identifier. As C++ program is built from C, the C++ compiler supports all the features of C. The following are the steps involved in writing, compiling and executing a C++ program : 1. Open Microsoft Visual C++ and type the program. 2. Save the file with the corresponding extension (filename.cpp) 3. Compile the program. 4. Build & execute/run the program. 2
- 3. F P 201 - PROGRAMMING FUNDAMENTAL Lab 1A Procedure : Step 1: Type the programs given below Step 2: Compile and run the program. Write the output. Step 3: Save the program as lab1A.cpp. The following program finds the sum of two numbers and displays it. // Program to add two numbers #include <iostream> using namespace std; void main() { int a, b, sum; a = 5; b = 2; sum = a + b; cout << "The sum is: " << sum << "n"; } Lab 1B Procedure : Step 1: Type the programs given below Step 2: Compile and run the program. Write the output. Step 3: Change the statement cout << "The sum is: " << sum; in line 9 to cout << "The average is: " << sum/2; Step 4: Save the program as lab1B.cpp. // Program to find the average of two numbers 3
- 4. F P 201 - PROGRAMMING FUNDAMENTAL #include <iostream> using namespace std; void main() { int a, b, sum; a = 5; b = 2; sum = a + b; cout << "The sum is: " << sum; } Lab 1C Procedure : Step 1: Type the programs given below Step 2: Compile and run the program. Write the output. Step 3: Save the program as lab1C.cpp. // The following program illustrates variable and // constant declaration. #include <iostream> using namespace std; const float PI = 3.14; void main() { double radius = 3.0; double circumference; circumference = 2 * PI * radius; cout << "Circumference = " << circumference <<endl; } Lab 1D Procedure : 4
- 5. F P 201 - PROGRAMMING FUNDAMENTAL Step 1: Type the programs given below Step 2: Compile and run the program. Write the output. Step 3: Save the program as lab1D.cpp. // The following program illustrates variable and // constant declaration. #include <iostream> #define PI 3.14 using namespace std; void main() { double radius = 3.0; double circumference; circumference = 2 * PI * radius; cout << "Circumference = " << circumference <<endl; } Lab 1E Procedure : Step 1: Type the programs given below Step 2: Compile and run the program. Write the output. Step 3: Save the program as lab1E.cpp. Program to show the declaration and initialization of variables with float, double, char, int and boolean data type. #include <iostream> using namespace std; void main() { char grade = 'F'; float price = 77.01; double average = 145525.92; bool boolean_variable = true; int age = 50; cout << price <<"t"<< average <<"t"<<grade<<"t"<< boolean_variable <<"t"<<age<<endl; 5
- 6. F P 201 - PROGRAMMING FUNDAMENTAL } Lab 1F Procedure : Step 1: Type the programs given below Step 2: Compile and run the program. Write the output. Step 3: Save the program as lab1F.cpp. Program to show the declaration and initialization of variables with string data type. // my first string #include <iostream> #include <string> using namespace std; void main () { string mystring = "This is a string"; cout << mystring; } LAB EXERCISE 1. Describe the functionality of using a. #include <string> as Preprocessor directives b. int main (void) as main function 2. For each statement below, write doen the suitable variable declaration: a. the number of month in a year b. the sum of x + y if given x = 5 and y = 10 6
- 7. F P 201 - PROGRAMMING FUNDAMENTAL 3. Based on IPO chart information below: a. Declare the variable in C++ by using the appropriate data type b. Transform the Algorithm into C++ code IPO Chart Information Input Processing Output Number of late days = 7 Calculate amount Display Number of late charge = 0.2 amount Algorithm 1. Declare the number of late days, late charges and amount 2. Calculate the amount by multiplying the number of late days with late charge 3. Display amount 7