Strings

Strings

• not first class data types in C (like int or float)

• really just character (char) arrays

• have a fixed maximum length

• can and often are indexed like arrays (from 0)

• need ‘terminating’ with an end of string marker (hidden character \0, the ASCII NUL character)

char z[] = "hello";

z[0] is ‘h’

z[5] is zero ‘\0’

Printing Strings

using %s

printf("You typed %s\n", answer); 

• Assuming ‘answer’ is either a char array or a pointer to a char 

char *answer = "hello"; 
char answer[] = "hello";

Get Strings

 using %s

char answer[20]; /*max length including \0 is 
20!*/
scanf("%s", answer);

Comparing Strings

compare the pointers to the locations not the actual data

strcmp()

compares 2 strings and returns -1, 0, 1 (less, equal, greater)

char *password = "pass123";
//...
if (strcmp(password, "pass123") == 0 ||
	strcmp password, "secret) == 0)
printf("Yes\n");

In <string.h>

int strlen(char *)/*find the length of string 
s*/
char *strchr(char , int)/*find a character 
within a string (pointer or NULL)*/
strcat(char *d, char *s)//append string s to d
strcpy(char *d, char *s)//copy string s to d