eliminating some string in string

Question

https://code.sololearn.com/cL6v2zNOcaTa/#c

I want to eliminate some string in string. get number and eliminate some string starting from end.

But I have some problem in this code.

Answer 1

str[len-num] Is a single character but the function strcpy expects a string. To get a string starting from the position len-num, you should add the index to the pointer directly, like this:

strcpy(str+len-num, str+len);

Answer 2

In addition to Kinshuk Vasisht's reply:

If you want to eliminate from the end you can just set the null character at that position like:
str[len - num] = '\0';

If you want to copy it to a new array you should probably use strncpy as it is more secure.
https://en.cppreference.com/w/c/string/byte/strncpy

char destination[128];
strncpy( destination, str, len - num );
destination[len - num] = '\0';