1. Strings
String constants
String variables
Traverse strings

2. String_ an array of characters terminated with an extra null character, ‘\0’
string constant_
“Enter YES or No: “
char *q = “Enter YES or No: “;
char *q; q = “Enter YES or No: “;
illegal: q[5] = ‘x’; q E n t e r
... N o : \0

3. Don’t forget to supply the trailing null character
string variable_
char q[18] = {‘E’,’n’,’t’,’e’,’r’,’ ‘,’Y’,’E’,’S’, ‘ ‘,’o’,’r’,’ ‘,’N’,’o’,’:’,’ ‘,’\0’};
char q[18] = “Enter YES or No: “;
illegal: char *q = “Enter YES or No: “; char qcopy[100]; qcopy = q;
Don’t forget to supply the trailing null character
when creating a string.
We can’t simply assign one character string to another,
just as we couldn’t assign arrays.

4. int getline(char line[], int max)/*
* Read a single input line into an array. */
#include <stdio.h>
int getline(char line[], int max) {
int c;
int i = 0;
while ((c = getchar()) != '\n')
if (i < max)
line[i++] = c;
line[i] = '\0';
return (i); }

5. strcat(s1,s2) strcpy(s1,s2) s2 s1 s2 s1 E F \0 A B C D \0 E F \0 A B C

6. strcmp(s1,s2) return 0 if equal
strlen(s) return length, not counting null character
strchr(s,c) return a pointer to the first occurrence of c in s, or NULL
getline(line, MAXLEN);
if (strcmp(line, "yes")==0 || strcmp(line, "YES")==0)
… ;

7. len = getline(inpline, MAXLEN); strcpy(newname, blankptr + 1); /*
* Name conversion program */
char inpline[MAXLEN + 1];
int len;
char newname[MAXLEN + 2];
char *blankptr; /* pointer to blank separator */
len = getline(inpline, MAXLEN);
blankptr = strchr(inpline, ' ');
strcpy(newname, blankptr + 1);
strcat(newname, ", ");
*blankptr = '\0';
strcat(newname, inpline);
printf("%s\n", newname);
Alex Quilici
Quilici, Alex

8. blankptr
inpline A l e x Q u i l i c i \0
newname Q u i l i c i \0
...

9. char *strcpy(char d[], char s[]){
int i;
for (i = 0; (d[i] = s[i]) != '\0'; i++);
return d; }
int strcmp(char s[], char t[])
for (i = 0; s[i] == t[i] && s[i] != '\0'; i++);
return s[i] - t[i];
int strlen(char s[])
for (i = 0; s[i] != '\0'; i++);
return i;

10. char *strcpy(char *dptr, char *sptr){
char * startptr = dptr;
for (; (*dptr = *sptr) != '\0'; dptr++, sptr++);
return startptr; }
int strcmp(char *sptr, char *tptr)
for (; *sptr == *tptr && *sptr != '\0'; sptr++, tptr++);
return *sptr - *tptr;
int strlen(char *ptr)
char *startptr = ptr;
for (; *ptr != '\0'; ptr++);
return ptr - startptr;