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Write your own memcpy() in C
Here we will see how to implement memcpy() function in C. The memcpy() function is used to copy a block of data from one location to another. The syntax of the memcpy() is like below −
void * memcpy(void * dest, const void * srd, size_t num);
To make our own memcpy, we have to typecast the given address to char*, then copy data from source to destination byte by byte. Just go through the following code to get better idea.
Example
#include<stdio.h> #include<string.h> void custom_memcpy(void *dest, void *src, size_t n) { int i; //cast src and dest to char* char *src_char = (char *)src; char *dest_char = (char *)dest; for (i=0; i<n; i++) dest_char[i] = src_char[i]; //copy contents byte by byte } main() { char src[] = "Hello World"; char dest[100]; custom_memcpy(dest, src, strlen(src)+1); printf("The copied string is %s
", dest); int arr[] = {10, 20, 30, 40, 50, 60, 70, 80, 90}; int n = sizeof(arr)/sizeof(arr[0]); int dest_arr[n], i; custom_memcpy(dest_arr, arr, sizeof(arr)); printf("The copied array is "); for (i=0; i<n; i++) printf("%d ", dest_arr[i]); }
Output
The copied string is Hello World The copied array is 10 20 30 40 50 60 70 80 90
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