Use C language. Analog Implementation Strcpy,strcat,strcat,memcpy,memmove

Source: Internet
Author: User

1. Analog implementation strcpy#include<stdio.h> #include <stdlib.h> #include <string.h> #include <assert.h> char *my_strcpy (CHAR&NBSP;*DST,&NBSP;CONST&NBSP;CHAR&NBSP;*SRC) {assert (dst != null); ASSERT (src  != null);char *ret = dst;while  ((*dst++ = *src++)  !=  ' + '); Return ret;} Int main () {char arr1[] =  "Hello world!!!"; char arr2[20];my_strcpy (ARR2,&NBSP;ARR1);p rintf ("%s\n", &NBSP;ARR2); System ("Pause");       return 0;} 2. Analog implementation strcat#include<stdio.h> #include <assert.h> #include <stdlib.h>char *strcat (char &NBSP;&NBSP;*DEST,&NBSP;CHAR&NBSP;CONST&NBSP;*SRC) { assert (dest); assert (SRC);char *temp =  dest;while  (*dest) {dest++;} while  (*SRC) {*dest++ = *src++;} *dest =  ' + '; return temp;} Int main () {char arr[50] =  "i come from china!!"; char *p =  " me too!! "; strcat (arr, p);p rintf ("%s",  arr); System ("pause");    return 0;} 3. Analog implementation of strcat#include<stdio.h> #include <assert.h> #include <stdlib.h>int my_strcmp (const &NBSP;CHAR&NBSP;*ARR1,&NBSP;CONST&NBSP;CHAR&NBSP;*ARR2) {assert (ARR1); assert (ARR2);while  (*arr1 == &NBSP;*ARR2) {if  (*arr1 ==  ') {return 1;}     arr1++;arr2++;} RETURN&NBSP;*ARR1&NBSP;-&NBSP;*ARR2;} Int main () {char *s1 =  "i am a student!"; char *s2 =  "i am a student!"; INT&NBSP;RET=MY_STRCMP (S1,&NBSP;S2);if  (ret == 1) {printf ("Two strings are the same! \ n ");} Else{printf ("Two string difference:%d\n",  ret);} System ("pause"); return 0;} 4. Analog implementation memcpy#include<stdio.h> #include <string.h> #include <assert.h> #include <stdlib.h> void *my_memcpy (void *dest, const void *src, size_t n) {assert (dest); Assert ( src);char *p =  (char *) dest;const char *q =  (char *) src;while  (n--) {*p = *q;p++;q++;} Return dest;} Int main () {int arr1[100] = { 1,2,3,4,5,6,7,8,9,10,11 };int arr2[100] =  { 0 };int i = 0;int num;printf ("Please enter the number of copies to be copied:"); scanf ("%d",  &num); my _memcpy (Arr2, arr1, 4*num);for  (i = 0; i < num; i++) {printf ("% d  ",  arr2[i]);} printf ("\ n"); system ("pause"); return 0;} 5. Analog implementation memmove#include<stdio.h> #include <string.h> #include <assert.h> #include <stdlib.h> void *my_memcpy (void *dest, const void *src, size_t n) {assert (dest); Assert ( SRC);char *p =  (char *) dest;const char *q =  (char *) src;if  ( P > q && p < q + n) {while  (n--) {  * (P  + n)  = * (q + n);}} else{while  (n--) {*p = *q;p++;q++;}} Return dest;} Int main ( ) {int arr[] = { 1, 2, 3, 4, 5, 6, 7,  8, 9, 10 };int i = 0;my_memcpy (arr+4, arr+2, 20);for  (i  = 0; i < 10; i++) {printf ("%d ",  arr[i]);} printf ("\ n"); system ("pause"); return 0;}


Use C language. Analog Implementation Strcpy,strcat,strcat,memcpy,memmove

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