в 14:20, 25 мая 2010

2010-05-25T14:20:56Z

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2010-05-25T10:22:20Z

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==A demonstration of seeking and finding==

<source lang="cpp">
#include <stdio.h>
#include <string.h>
void main()
{
char str1[] = "This string contains the key.";
char str2[] = "the key";
char str3[] = "the keys";
if(strstr(str1, str2) == NULL)
printf("\nString not found.");
else
printf("\nString: %s\n was found in string: %s",str2, str1);
if(strstr(str1, str3) == NULL)
printf("\nString not found.");
else
printf("\nWe shouldn"t get to here!");
}

</source>

== Find character in string: how to use strchr==

<source lang="cpp">
#include <stdio.h>
#include <string.h>
int main ()
{
char str[] = "This is a line";
char *p;

printf ("Looking for "s" character in \"%s\"...\n", str);

p = strchr(str, "s");

while (p != NULL) {
printf ("found at %d\n",p - str + 1);
p = strchr(p + 1, "s");
}
return 0;
}

</source>

==Finding occurrences of one string in another: strstr==

<source lang="cpp">
#include <stdio.h>
#include <string.h>
#include <ctype.h>
void main() {
char text[100];
char substring[40];
int i = 0;

printf("\n string to be searched(less than 100 characters):\n");
gets(text);

printf("\n string sought (less than 40 characters ):\n");
gets(substring);

/* Convert both strings to upper case. */
for(i = 0 ; (text[i] = toupper(text[i])) != "\0" ; i++);
for(i = 0 ; (substring[i] = toupper(substring[i])) != "\0" ; i++);
printf("\nThe second string %s found in the first.\n",
((strstr(text, substring) == NULL) ? "was not" : "was"));
}

</source>

== Find last occurrence of character in string==

<source lang="cpp">
#include <string.h>
#include <stdio.h>
int main(void)
{
char *p;
p = strrchr("this is a test", "i");
printf(p);
return 0;
}

</source>

== Find last occurrence of character in string: how to use strrchr==

<source lang="cpp">
#include <stdio.h>
#include <string.h>
int main ()
{
char str[] = "This is a line";
char *p;

p = strrchr(str, "i");
printf ("Last occurence of "i" is %d \n", p - str + 1);

return 0;
}

</source>

== Find substring==

<source lang="cpp">
#include <string.h>
#include <stdio.h>
int main(void)
{
char *p;
p = strstr("this is a test", "is");
printf(p);
return 0;
}

</source>

== Find substring: how to use strstr==

<source lang="cpp">
#include <stdio.h>
#include <string.h>
int main ()
{
char str[] ="This is a line";
char *p;

p = strstr (str, "is");
strncpy (p, "sample",5 );
puts (str);

return 0;
}

</source>

==Find sub string: our own function==

<source lang="cpp">
#include <stdio.h>
int find_substr(char *listPointer, char *itemPointer);
int main(void)
{
if(find_substr("C is fun", "is") != -1)
printf("Substring is found.");
return 0;
}
/* Return index of first match of itemPointer in listPointer. */
int find_substr(char *listPointer, char *itemPointer)
{
int t;
char *p, *p2;
for(t=0; listPointer[t]; t++) {
p = &listPointer[t];
p2 = itemPointer;
while(*p2 && *p2==*p) {
p++;
p2++;
}
if(!*p2) return t; /* 1st return */
}
return -1; /* 2nd return */
}

</source>

==Look up names in a hardcoded list==

<source lang="cpp">
#define STRING_LENGTH 80
#include <stdio.h>
#include <string.h>
int lookup(char const *const name); /* lookup a name */
int main()
{
char name[STRING_LENGTH] = "Jim";
name[strlen(name)] = "\0";
if (lookup(name)){
printf("%s is in the list\n", name);
}else{
printf("%s is not in the list\n", name);
}
return (0);
}
int lookup(char const *const name)
{
static char *list[] = {"John","Jim","Jane","Clyde",NULL};
int index;
for (index = 0; list[index] != NULL; ++index) {
if (strcmp(list[index], name) == 0)
return (1);
}
return (0);
}

</source>

== Scan string for specified characters==

<source lang="cpp">
#include <stdio.h>
#include <string.h>
int main(void)
{
char *p;
p = strpbrk("this is a test", " absj");
printf(p);
return 0;
}

</source>

== Scan string for specified characters: how to use strpbrk==

<source lang="cpp">
#include <stdio.h>
#include <string.h>
int main ()
{
char str[] = "This is a line";
char key[] = "aeiou";
char *p;
printf ("Vowels in "%s": ",str);
p = strpbrk (str, key);
while (p != NULL) {

printf ("%c " , *p);
p = strpbrk (p + 1, key);

}
printf ("\n");

return 0;
}

</source>

==Search a char inside a string==

<source lang="cpp">
#include <stdio.h>
#include <string.h>
int main(void)
{
char *p;
p = strchr("this is a test", " ");
printf(p);
return 0;
}

</source>

==Search string==

<source lang="cpp">
#include <stdio.h>
#include <string.h>
int search(char *p[], char *name);
char *names[] = {"John","Jim","Jane","James",NULL};
int main(void)
{
if(search(names, "James") != -1)
printf("in list.\n");
if(search(names, "Bill") == -1)
printf("not found.\n");
return 0;
}
int search(char *p[], char *name)
{
int t;
for(t=0; p[t]; ++t){
if(!strcmp(p[t], name)) {
return t;
}
}
return -1; /* not found */
}

</source>

== Search string for occurrence of character set==

<source lang="cpp">
#include <string.h>
#include <stdio.h>
int main(void)
{
int len;
len = strcspn("this is a test", "ab");
printf("%d", len);
return 0;
}

</source>

== Search string for occurrence of character set: how to use strcspn==

<source lang="cpp">

#include <stdio.h>
#include <string.h>
int main ()
{
char str1[] = "1245789000";
char str2[] = "1234567890";
int i;
i = strcspn (str1,str2);
printf ("The first number in str1 is str1[%d]\n", i);
return 0;
}

</source>

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в 14:20, 25 мая 2010

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