Lecture 01

Computational Methods Lab

Computational Methods Laboratory

Bernhard Egwolf

University of Santo Tomas

College of Science

Bernhard Egwolf University of Santo Tomas


C Programming

We start with an introduction to the programming language C.

Minimum requirements for C programming:

Text editor for writing source code.

C compiler for creating an executable program.

Console for executing program.

WikiBook C Programming:http://en.wikibooks.org/wiki/C_Programming



Visual C++

We will use Microsoft Visual C++, an Integrated DevelopmentEnvironment (IDE).

It can be used for C and C++ programming and it comes with

text editor (typing source code),

C/C++ compiler (creating executable program),

debugger (finding errors),

console (running program),

learning resources(http://msdn.microsoft.com/en-us/visualc/),

and many more useful things.

Microsoft Visual C++ Express Edition is free.



Start Visual C++

Start → All Programs → Microsoft Visual Studio... → MicrosoftVisual C++...



Create Project

File → New → Project

Choose Empty Project, give it the name hello, and press OK.



Create Source Code File

Go to the Solution Explorer window.

Click with the right mouse key on Source Files.

Add → New Item



Create Source Code File

Choose C++ File, give it the name hello.c, and press Add.



Create Your First C Program

Type your first program into the hello.c file.




#include <stdio.h>

int main()

{

printf( "Hello World!\n" );

getchar();

return 0;

}




Debug → Start Debugging (Check Output window for errors!)

This compiles the program and opens a console with the output:

Press Enter to close the console.



Your First C Program

#include <stdio.h>

int main()

{


getchar();

return 0;

}



Adding Comments

// Pre-compiler directive.

#include <stdio.h>

/* Every C program starts with the

function main(). */

int main()

{


getchar();

return 0;

}



Integer Variables

#include <stdio.h>

int main()

{

int i, j, k;

i = 7;

j = 3;

k = i + j;

printf( "k = %d\n", k );

getchar();

return 0;

}



Integer Variables

Compile hello.c and run program (Debug → Start Debugging).Press Enter to close the console.

Declaring integer variables:int i, j, k;

int (–2,147,483,648 to 2,147,483,647)unsigned int (0 to 4,294,967,295)short int (–32,768 to 32,767)

The basic arithmetic operators for integers are:

+ addition

− subtraction

∗ multiplication

/ division (integer division)

% modulo



Floating Point Variables

#include <stdio.h>

int main()

{

int i, j, k;

float a, b;

i = 7;

j = 3;

k = i / j;

a = 7 / 3;

b = 7.0 / 3.0;

printf( "k = %d\n", k );

printf( "a = %f, b = %f\n", a, b );

getchar();

return 0;

}




Debug → Start Debugging

This compiles the program and opens a console with the output(note difference between integer and floating point division):

Press Enter to close the console.Bernhard Egwolf University of Santo Tomas



Declaring floating point variables:float a, b;

float (3.4E +/- 38 (7 digits))double (1.7E +/- 308 (15 digits))

The basic arithmetic operators for floating point numbers are:

+ addition

− subtraction

∗ multiplication

/ division (be careful with integer variables)



If Conditions

#include <stdio.h>

int main()

{

int i, j;

i = 7;

j = 3;

if(i > j)

{

printf( "i > j!\n" );

}

else

{

printf( "i <= j!\n" );

}

getchar();

return 0;

}



If Conditions

Compile hello.c and run program (Debug → Start Debugging).Press Enter to close the console.

if(condition 1)

{

commands;

}

else if(condition 2)

{

commands;

}

else

{

commands;

}



If Conditions

Comparison operators:

< less than

> greater than

<= less than or equal to

>= greater than or equal to

== equal to (note that a single = will not work!)

! = not equal to

Logical Operators:

&& logical and

|| logical or

! logical not

Example:if((x <= y) && !(y > z))



Reading an Integer Variable from Console

#include <stdio.h>

int main()

{

int temp;

printf("What is the temperature in degrees Celsius? ");

scanf("%d", &temp);

printf("%d degrees Celsius is nice.\n", temp);

getchar();

getchar();

return 0;

}



If Condition

...

printf("What is the temperature in degrees Celsius? ");

scanf("%d", &temp);

if(temp > 35)

{

printf("%d degrees Celsius is hot.\n", temp);

}

else

{


}

getchar();

getchar();

...



If Condition

...

scanf("%d", &temp);

if(temp > 35)

{

printf("%d degrees Celsius is hot.\n", temp);

}

else if(temp < 20)

{

printf("%d degrees Celsius is cold.\n", temp);

}

else

{


}

getchar();

...Bernhard Egwolf University of Santo Tomas


Acknowledgments

This presentation was based on tutorials from the following webpages:

http://www.idleloop.com/tutorials/introC/

http://www.cprogramming.com/tutorial/c/lesson1.html

http://en.wikibooks.org/wiki/C_Programming


Lecture 01

Documents

Transcript of Lecture 01