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Programming in C - Programming in C - 22Dr. Heru Santoso BRDr. Heru Santoso BR

Hello, World1. /* Hello, world program */2.#include <stdio.h>3. 4. int main()5. {6. printf("hello, ");7. printf("world\n");8. return 0;9. }

Basic Programming Concepts

• Comment To explain what the program is for and why it is the way it is.

• Preprocessing Done before the program is compiled.• To include header files containing

information about C libraries• Statement A line of code that tells

computer to perform some action. Always ended with a semicolon(;).• Invoking functions

• Function A module often consisting of a set of statements.• Two functions in the hello world

program: main, printf

1. /* Hello, world program */

2. #include <stdio.h>3. 4. int main()5. {6. printf("hello, ");7. printf("world\n");8. return 0;9. }

Programming Concepts

• /* Hello, world program */

• #include <stdio.h>• • int main()• {• printf("hello, ");• printf("world\n");• return 0;• }

Statements : • calling function printf(“hello,”);

printf(“world\n”);

Nama fungsi

argument

Should be ended with

“;”

Nama fungsi

argument

Escape sequence

In Class Exercise 1-1

• Escape Sequences are used to control printf to do something other than printing characters.

• Modify the hello world program to try out various escape sequences like:• \n: Newline. Position cursor at the

beginning of the next line.• \t: Tab. Move cursor to the next tab stop.• \a: Alert. Sound the system bell.

Arithmetic Operators• To form expressions

• Many statements are merely expressions.

• Normal order of operations (+, - ; *,/) is followed. Parentheses can be used.

• 4+3*2 = 4+9=13• (4+3)*2=14

+ Addition

- Subtraction

* Multiplication

/ Division

%Modulus (remainder)

++ Increment

-- Decrement

Arithmetic Operators: An Example

1. /* Arithmetic operators */2. #include <stdio.h>3. 4. int main()5. {6. printf("7+3=%d\n",7+3);7. printf("7-3=%d\n",7-3);8. printf("7*3=%d\n",7*3);9. printf("7/3=%d\n",7/3);10. printf("7%%3=%d\n",7%3);11. printf("7.0/3.0=%f\n",7.0/3.0);12. return 0;13.}

Variables

• Variable Name for a memory object. Variable names must start with letters and contain letters, digits, and underscores. • a, b, i, j, counter, number_of_points, c1234, …

• Type What the variable represents. Could be of integer, floating point number, character, string, and many others.• int, float, double, char, …

• Declaration Tells compiler about variables and their type. • int i,j;• float sum;

Numeric Typesint integer

float floating point

charcharater (a very shot integer)

short or short int

short integer

long or long int

long integer

double long floating point

long doublevery long floating point

Reading Inputs1. #include <stdio.h>2. int main()3. {4. float a,b;5. printf("Please input the first number:\n");6. scanf("%f",&a);7. printf("Please input the second number:\n");8. scanf("%f",&b);

9. printf("a+b=%f\n",a+b);10. printf("a-b=%f\n",a-b);11. printf("a*b=%f\n",a*b);12. printf("a/b=%f\n",a/b);13.}

Assignment1. /* Arithmetic operators */2. #include <stdio.h>3. 4. int main()5. {6. int a,c;7. int b=4;8. a=3;9. c=a+b;10. printf(“Sum: %d + %d -> %d\n”,a,b,c);11. a++;b--;12. prinf(“Now a=%d and b=%d\n”,a,b);13. return 0;14.}

In-Class Exercise 1-2

• Write a program to calculate the average of three floating point numbers, namely 2.3, 3.4, 4.5.• Using scanf function• Using assignment