UMBC CMSC 201 Fall '06 CSEE | 201 | 201 F'06 | lectures | news | help Search Notes:

# Using variables

### The Program

/*************************************************** ** File: wreck.c ** Author: Sue Bogar ** Date written: 9/2/95 ** Section: 101 ** E-Mail: bogar@cs.umbc.edu ** A program that prints the depth of the wreck of ** the Hesperus using 3 different units of measure: ** fathoms, feet, and inches. ****************************************************/ #include <stdio.h> int main() { /* Declare variables */ int inches, feet, fathoms; /* Assign fathoms the depth of the wreck */ fathoms = 7; /* Do conversions into feet or inches */ feet = 6 * fathoms; inches = 12 * feet; /* Print out the depths */ printf ("\nIts depth at sea: \n"); printf (" %d fathoms \n", fathoms); printf (" %d feet \n", feet); printf (" %d inches \n", inches); return 0; }

### The Output

linux1[78]% gcc -Wall -ansi wreck.c linux1[79]% a.out Its depth at sea: 7 fathoms 42 feet 504 inches

# Declaring variables

At the line:

int inches, feet, fathoms;

# Constants

0 77

### These are not good integer constants

1234567890 /* Legal, but might be too large */ 0123 /* Legal, but in octal (base 8) */ 123.0 /* A floating point constant */

### What is an "integer expression"?

An "expression" is either a constant, variable, or the result of operators involving expressions. So, an integer expression is an integer constant, an integer variable, or the result of an integer-producing set of operations on expressions.

### Examples of floating point constants

3.14159 314.159e-2

### These are not good floating point constants

3,141.59 /* No commas allowed */ 314159 /* This is an integer constant */

'a' '3'

### Examples of string constants

"Hello World" "Charlie Brown and Snoopy" "" /* the empty string */ " " /* string of spaces */ /* "This is a comment" */

## An example showing assignment to different data types

### The Program

/**************************** ** File: example.c ** Author: Sue Bogar ** Date: A long time ago ** Section: 1 ** EMail: bogar@cs.umbc.edu ** ** An example program to show assigning ** constants to different data types. *******************************/ #include <stdio.h> int main() { /*Declare variables */ int i; double x; char c; /* Assign values to a variable of type int */ /* and print them */ i = 345; printf("The variable i contains: %d\n", i); i = 678; printf("The variable i contains: %d\n", i); i = 123.74; printf("The variable i contains: %d\n\n", i); /* Assign a value to a variable of type */ /* double and print it */ x = 314.159e-2; printf("The variable x contains: %f\n", x); x = 12; printf("The variable x contains: %f\n\n", x); /* Assign a value to a variable of type */ /* char and print it */ c = 'a'; printf("The variable c is %c character.\n", c); return 0; }

### The Output

linux1[80]% gcc -Wall -ansi example.c linux1[81]% a.out The variable i contains: 345 The variable i contains: 678 The variable i contains: 123 The variable x contains: 3.141590 The variable x contains: 12.000000 The variable c is a character. linux1[82]%

CSEE | 201 | 201 F'06 | lectures | news | help