1. Engr 0012 (04-1) LecNotes 24-01

2. strings strings are an array of type char string declaration
// include libraries
#include<string.h>
// defined constants
#define MAXSTRING 11
main()
{ // begin main
// variable declaration
char string1[ ] = "A string";
char string2[5];
char string3[MAXSTRING];
int numchar, order;
string declaration
include string library
used defined constant
for max length + 1
memory “map”
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NULL
|?|?|?|?|?|
|?|?|?|?|?|?|?|?|?|?|?|
Engr 0012 (04-1) LecNotes 24-02

3. strings string initialization “hardwire” at declaration
// include libraries
#include<string.h>
// defined constants
#define MAXSTRING 11
main()
{ // begin main
// variable declaration
char string1[ ] = "A string";
char string2[5];
char string3[MAXSTRING];
int numchar, order;
string initialization
“hardwire” at declaration
|A| |s|t|r|i|n|g||
use strcpy function
// string initialization
strcpy(string2,"hi");
|h|i||?|?|
get it from the keyboard
// string initialization
printf("\nEnter a string \n==> ");
fflush(stdin);
scanf("%[^\n]", string3);
best - read until return
|H|i| |t|h|e|r|e|!||?|
// string initialization
printf("\nEnter a string \n==> ");
fflush(stdin);
scanf(" %s", string3);
not as good
|H|i||?|?|?|?|?|?|?|?|
Engr 0012 (04-1) LecNotes 24-03

4. strings string display string placeholder is %s string1 = A string
// displaying strings
printf( "\n\nstring1 = %s", string1 );
printf( "\n\nstring2 = %s", string2 );
printf( "\n\nstring3 = %s", string3 );
string placeholder is %s
string1 = A string
string2 = hi
string3 = Hi there!
Engr 0012 (04-1) LecNotes 24-04

5. strings copying strings - strcpy
strcpy( string3, string1);
printf( "\n\nstring1 = %s", string2 );
printf( "\n\nstring3 = %s", string3 );
copies contents of second argument into first argument
==> copies string1 into string3
string1 before
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string3 before
|H|i| |t|h|e|r|e|!||?|
string3 after
|A| |s|t|r|i|n|g|||?|
string1 = A string
string3 = A string
display
Engr 0012 (04-1) LecNotes 24-05

6. strings string length - strlen display
numchar = strlen( string3 );
printf("\n\nnum char in \"%s\" : %d", string3, numchar );
strlen counts characters until NULL is reached
string3
|A| |s|t|r|i|n|g|||?|
num char in "A string" : 8
display
Engr 0012 (04-1) LecNotes 24-06

7. strings comparing strings - strcmp display
// compare strings
order = strcmp( string1, string2);
if ( order < 0 )
{ printf( "\n\n%s before %s", string1, string2 ); }
else if ( order == 0 )
{ printf( "\n\n%s equals %s", string1, string2 ); }
else
{ printf( "\n\n%s after %s", string1, string2 ); }
strcmp determines alphabetical order of two strings
string1
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string2
|h|i||?|?|
A string before hi
display
Engr 0012 (04-1) LecNotes 24-07

8. strings parameters in function calls strings are an array of type char
parameter useage follows same rules as any array
// prototypes
void getstring( char string[] );
formal parameter requires type (char), name, and [ ] to designate array
main()
{ …
getstring( string3 );
actual parameter requires local name
Engr 0012 (04-1) LecNotes 24-08