Write a function that extracts a substring from a string.

The function prototypes are as follows:

int substr (char dst[], char src[], int start, int len) {}

The goals are:

Starting from the start position of the SRC array, the position of the start character is shifted backwards,

Copies up to Len non-nul characters to a DST array. After replication is complete, the DST array must be

Ends with a nul byte. The return value of the function is the length of the string stored in the DST array.

#include <stdio.h>

int main ()

{

Char dst[10];

Char src[] = "Hello-wellcome";

substr (DST, SRC, 6, 8);

printf ("%d\n", sizeof (DST));

printf ("%d\n", strlen (DST) +1);

printf ("%s\n", DST);

System ("pause");

return 0;

}

int substr (char dst[], char src[], int start, int len)

{

char* sc = src + start;

ASSERT (DST! = null&&src! = NULL);

int n, i=0;

n = strlen (SC);

if (n < len)//Copy Len

{

Len = n;

}

while (LEN)

{

Dst[i] = Sc[i];

len--;

i++;

}

Dst[i] = ";

}

Write a function that extracts a substring from a string.