String .h

String.h- This header file defines several functionsto manipulate C strings and arrays.Functions declared in string.h are extremely popularsince as a part of the C standard library, they are guaranteed to work on any platform which supports CSome of its functions are defined below .

Memcpy:- UseCopy block of memory SYNOPSIS#include <string.h> void *memcpy(void *s1, const void *s2, size_tn); DESCRIPTIONThe memcpy() function copies n bytes from the object pointed to by s2 into the object pointed to by s1. If copying takes place between objects that overlap, the behaviour is undefined. RETURN VALUEThe memcpy() function returns s1; no return value is reserved to indicate an error.

Example/* memcpy example */#include <stdio.h>#include <string.h> int main (){ char str1[]="Sample string"; char str2[40]; char str3[40];memcpy (str2,str1,strlen(str1)+1);memcpy (str3,"copy successful",16);printf ("str1: %s\nstr2: %s\nstr3: %s\n",str1,str2,str3); return 0;}Outputstr1: Sample stringstr2: Sample stringstr3: copy successful

memmovememmoveMemmove:-UseMove block of memorySYNOPSIS#include <string.h> void *memmove(void *s1, const void *s2, size_tn); DESCRIPTIONThe memmove() function copies n bytes from the object pointed to by s2 into the object pointed to by s1. Copying takes place as if the n bytes from the object pointed to by s2 are first copied into a temporary array of n bytes that does not overlap the objects pointed to by s1 and s2, and then the n bytes from the temporary array are copied into the object pointed to by s1. RETURN VALUEThe memmove() function returns s1; no return value is reserved to indicate an error.

Example/* memmove example */ #include <stdio.h> #include <string.h>int main () { char str[] = "memmove can be veryuseful......";memmove (str+20,str+15,11); puts (str); return 0;}}}Outputmemmove can be very very useful.

Memcmp :-UseCompare two blocks of memorySYNOPSIS#include <string.h> intmemcmp(const void *s1, const void *s2, size_tn); DESCRIPTIONThe memcmp() function compares the first n bytes of the object pointed to by s1 to the first nbytes of the object pointed to by s2. The sign of a non-zero return value is determined by thesign of the difference between the values of the first pair of bytes that differ in the objects being compared. RETURN VALUEThe memcmp() function returns an integer greater than, equal to or less than 0, if the object pointed to by s1 is greater than, equal to or less than the object pointed to by s2 respectively.

Example/* memcmp example */#include <stdio.h>#include <string.h> int main (){ char str1[256]; char str2[256];int n;size_t len1, len2;printf ("Enter a sentence: "); gets(str1);printf ("Enter another sentence: "); gets(str2); len1=strlen(str1); len2=strlen(str2); n=memcmp ( str1, str2, len1>len2?len1:len2 ); if (n>0) printf ("'%s' is greater than '%s'.\n",str1,str2); else if (n<0) printf ("'%s' is less than '%s'.\n",str1,str2); else printf ("'%s' is the same as '%s'.\n",str1,str2); return 0;}OutputEnter a sentence: buildingEnter another sentence: book'building' is greater than 'book'

Memset:-UseFill block of memorySYNOPSIS#include <string.h> void *memset(void *s, intc, size_tn); DESCRIPTIONThe memset() function copies c (converted to an unsigned char) into each of the first n bytes of the object pointed to by s. RETURN VALUEThe memset() function returns s; no return value is reserved to indicate an error.

Example/* memset example */#include <stdio.h>#include <string.h> int main (){ char str[] = "almost every programmer should know memset!";memset (str,'-',6); puts (str); return 0;}Output------ every programmer should know memset!

MemchrUseLocate character in block of memory SYNOPSIS#include <string.h> void *memchr(const void *s, intc, size_tn); DESCRIPTIONThe memchr() function locates the first occurrence of c (converted to an unsigned char) in the initial n bytes (each interpreted as unsigned char) of the object pointed to by s. RETURN VALUEThe memchr() function returns a pointer to the located byte, or a null pointer if the byte does not occur in the object.

Example/* memchr example */#include <stdio.h>#include <string.h> int main (){ char * pch; char str[] = "Example string";pch = (char*) memchr (str, 'p', strlen(str)); if (pch!=NULL)printf ("'p' found at position %d.\n", pch-str+1); elseprintf ("'p' not found.\n"); return 0;}Output'p' found at position 5.

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String .h

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String .h