for (i=0;i<copy_this;i++)
   *(to_copy+i)=*(from_copy+i);

for (i=0;i<copy_this;i++)
   to_copy[i]=from_copy[i];

0K>for (i=0;i<copy_this;i++)
0K>   *(to_copy+i)=*(from_copy+i);
0K>

char *pfrom = from_copy;
char *stop_copy = from_copy + copy_this;
char *pto = to_copy;
for (; pfrom != stop_copy; ++pfrom)
{
    *pto = *pfrom;
    ++pto;
}

N>char *pfrom = from_copy;
N>char *stop_copy = from_copy + copy_this;
N>char *pto = to_copy;
N>for (; pfrom != stop_copy; ++pfrom)
N>{
N>    *pto = *pfrom;
N>    ++pto;
N>}

while (pfrom != stop_copy)
    *pfrom++ = *pto++;

for (i=0;i<copy_this;i++)
   i[to_copy]=i[from_copy];

for(char *p = some_str; *p; ++p) { char c = *p; ... }

for(int i = 0; i < length_of_some_str; ++i) { char c = s[i]; ... }

B>>for(i=0; i < copy_this; to_copy[i]=from_copy[i++]);
B>>

for(i=0; i < copy_this; to_copy[i]=from_copy[i], ++i);

Pzz>Это потому, что вы никогда не знаете, перегружены ли у вас квадратные скобки

for (int i=0;i<copy_this;i++)
   i[to_copy]=i[from_copy];

LS>for (i=0;i<copy_this;i++)
LS>   i[to_copy]=i[from_copy];
LS>

for(i=0; i < copy_this; to_copy[i]=from_copy[i++]);

std::copy(from_copy, from_copy + copy_this, to_copy);

The result of the postfix ++ operator is the value of the operand. After the result is
obtained, the value of the operand is incremented.

int i = 0;
i = i++;

#include <iostream>

int main() {
    int a[5] = {0};
    int b[5] = {1, 2, 3, 4, 5};
    
    for (int i = 0; i < 4; a[i] = b[i++]) {}
    
    for (int i = 0; i < 5; i++) {
        std::cout << a[i] << " ";
    }
    
    return 0;
}