copy a number of characters to another string in c without standard library

To copy a number of characters from one string to another without using the standard library in C, you can follow these steps:

1. Declare two character arrays, one for the source string and one for the destination string. For example:

char source[] = "Hello, world!";
char destination[20];

1. Determine the number of characters you want to copy from the source string to the destination string. Let's say you want to copy 5 characters.

2. Use a loop to iterate over the characters in the source string and copy them to the destination string. You can use the index variable of the loop to keep track of the number of characters copied. Here's an example:

int numCharactersToCopy = 5;
int i;
for (i = 0; i < numCharactersToCopy; i++) {
  destination[i] = source[i];
}

1. To complete the destination string, add a null character ('\0') at the end. This ensures that the destination string is properly terminated. You can do this by assigning the null character to the next index after the last copied character:

destination[i] = '\0';

1. The copied characters are now stored in the destination string. You can print the destination string to verify the result:

printf("Copied string: %s\n", destination);

This approach allows you to copy a specific number of characters from one string to another without using the standard library functions like strcpy or strncpy.