2009 McGraw-Hill, Inc. All rights reserved.

C for Engineers and Scientists: An Interpretive Approach

Discussion 1

• Commonly used commands• Executing program hello.c using Ch in ChIDE• A sample problem: find the volume of a cylinder• The _chrc and .chrc start-up file• The _path system variable

2009 McGraw-Hill, Inc. All rights reserved.

C for Engineers and Scientists: An Interpretive Approach

Commonly Used CommandsCh supports all Windows commands and most Unix commands

Command Usage Description

cd cd Change to the home directory

cd dir Change to the directory dir

cp cp file1 file2 Copy file1 to file2

ls ls List contents in the working directory

mkdir mkdir dir Create a new directory dir

pwd pwd Print (display) the name of the working directory

rm rm file remove file

chmod chmod +x file Change the mode of file to make it executable

chide chide file.c Edit and execute program file.c

vi vi file Edit file

2009 McGraw-Hill, Inc. All rights reserved.

C for Engineers and Scientists: An Interpretive Approach

• Examples of Commands

C:/Documents and Settings/Administrator> cd /C:/> mkdir tmpC:/> cd tmpC:/tmp> mkdir eme5C:/tmp> cd eme5C:/tmp/eme5> pwdC:/tmp/eme5C:/tmp/eme5> cp C:/Ch/demos/bin/hello.c hello.cC:/tmp/eme5> lshello.cC:/tmp/eme5> chide hello.c

2009 McGraw-Hill, Inc. All rights reserved.

C for Engineers and Scientists: An Interpretive Approach

Executing Program hello.c Using Ch in ChIDE

Click “Run” or “Start” to execute the program

2009 McGraw-Hill, Inc. All rights reserved.

C for Engineers and Scientists: An Interpretive Approach

• Files in Ch

C:/Ch> pwdC:/ChC:/Ch> lsbin/ demos/ docs/ include/ license/ README.TXT sbin/config/ dl/ extern/ lib/ package/ release/ toolkit/C:/Ch> cd docsC:/Ch/docs> C:/Ch/docs> lsREADME.TXT chguide.pdf chinstall.pdf chref.pdf man/

2009 McGraw-Hill, Inc. All rights reserved.

C for Engineers and Scientists: An Interpretive Approach

Using GIMP to grab an image

• Download GIMP from http://www.gimp.org/windows/ http://www.gimp.org/macintosh/

• Install GIMP

• Click menu File• Click menu Create• Click menu Screen Shot• Click Grab. Then move the cursor to a window to be

acquired.

• Save or print out the acquired window.

2009 McGraw-Hill, Inc. All rights reserved.

C for Engineers and Scientists: An Interpretive Approach

Example 1

• Find the volume of a cylinder– Radius: 3.5m– Height: 4.6m

2009 McGraw-Hill, Inc. All rights reserved.

C for Engineers and Scientists: An Interpretive Approach

Example 1 (cont.)

• Find the volume of a cylinder

/* File: cylinder.cCalculate and display the volume of the cylinder withthe radius of 3.5 meters and height of 4.6 meters */

#include<stdio.h>

int main() { printf("volume = %f m^3\n",  3.14159*3.5*3.5*4.6); return 0;

}

2009 McGraw-Hill, Inc. All rights reserved.

C for Engineers and Scientists: An Interpretive Approach

Example 2

• Write a program that calculates the area of a rectangle. The length and width of the rectangle are specified in the program.

2009 McGraw-Hill, Inc. All rights reserved.

C for Engineers and Scientists: An Interpretive Approach

Example 2 (cont.)/* File: area.c */#include <stdio.h>

int main() { double l, w, a; l = 2.5; /* length 2.5 meters */ w = 3.6; /* width 3.6 meters */ a = l*w;

printf(“The area is %f m^2\n”, a);

return 0;

}

2009 McGraw-Hill, Inc. All rights reserved.

C for Engineers and Scientists: An Interpretive Approach

The _chrc and .chrc start-up file

• The file _chrc in Windows and .chrc in Unix and Mac is the individual start-up file in your home directory, and will be invoked each time when Ch is launched.

2009 McGraw-Hill, Inc. All rights reserved.

C for Engineers and Scientists: An Interpretive Approach Open the startup file _chrc in Windows or

.chrc for Unix for editing through ChIDE

2009 McGraw-Hill, Inc. All rights reserved.

C for Engineers and Scientists: An Interpretive Approach

The _path system variable

• The variable _path in the _chrc or .chrc file is used to set up paths for executable files.