Question

Using pointer arithmetic, it’s possible to assign characters from one array to another. My question is, how does one do it given arbitrary start and stop points?

int main(void)
{
    char string1[] = "something"; //[s][o][m][e][t][h][i][n][g][\0]
    int start = 2, count = 3;
    char string2[10] = {0};
    char *ptr1 = &string1[start];
    char *ptr2 = string2;
    while (*ptr2++ = *ptr1++) { } //but stop after 3 elements???
    printf("%s",&string2);
}

There’s some kind of pointer arithmetic I’m missing to count/test the quantity of elements in a particular array. I do NOT want to declare an integral to count the loop! I want to do it all using pointers. Thanks!

Answer 1

#include <stdio.h>

int main(void)
{
    char string1[] = "something"; //[s][o][m][e][t][h][i][n][g][\0]
    int start = 2, count = 3;
    char string2[10] = {0};
    char *ptr1 = &string1[start];
    char *stop = ptr1 + count;
    char *ptr2 = string2;
    while ((ptr1 < stop) && (*ptr2++ = *ptr1++));
    printf("%s",string2);
    return 0;
}