Adding every other element from one array to another in C - c

Question

so I read in a string of characters from a file into an array called source. Now I want to split that array into 2 other more arrays, one containing all of the even indexes and the other containing the odd indexes of the source array.
This is the code i currently have, and I'm trying to accomplish this in the reachable function.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "graph.h"
void getfile(char[], char[]);
void reachable(char[]);
int size;
int i;
////////////GETFILE FUNCTION/////////////
void getfile(char *graph, char *source) {
FILE *infile;
infile = fopen(graph, "r");
if (infile == NULL) {
fprintf(stderr, "Can't open input file %s!\n", graph);
exit(1);
}
while (fscanf(infile, "%s", &source[i]) != EOF) {
++i;
}
fclose(infile);
size = strlen(source);
printf("%s\n", source);
reachable(&source[0]);
}
///////////REACHABLE FUNCTION////////////
void reachable (char *source){
char odd[100];
odd[100] ='\0';
char even[100];
even[100] = '\0';
for (i = 0; i<size; i+=2){
// printf("%c", source[i]); // when I run this line, I get the output I want
odd[i] = source[i]; // so why doesn't this put the output into the odd array?
}
for (i = 1; i<size; i+=2){
even[i] = source[i];
}
printf("%s\n", odd);
// printf("%s\n", even);
}
Any ideas why this doesn't work?
This is the string stored in source:
rlxrtgacufkrzyngilzxazrasjsbjqqitxmewplhtwzgxhokfmadrv
and this is the output I want for even and odd.
even: lrgcfryglxzajbqixephwghkmdv
odd: rxtaukznizarssjqtmwltzxofar
Any ideas on how to do this?
Thanks in advance!

Answer 1

You insert the values into odd and even at the exact same place as it is originally stored in source.
You need to have another counter than i for the destination array:
int destPlace = 0;
for (i = 1; i<size; i+=2) {
odd[destPlace] = source[i];
destPlace++;
}
And then the same procedure for even array.
Please note that in your code, both odd and even start on the same index, and it's not even the first which is source[0].

Answer 2

All right, assuming you did code you main function correctly,
Check:
char odd[100];
odd[99] ='\0'; //odd array has index from 0 to 99, not 100
char even[100];
even[99] = '\0'; //same here
You have to keep track of both odd/even index and source index.
int spliti, srci;
spliti=0, srci=0; // odd index starts with 0 in C
while (srci < size) {
odd[spliti] = source[srci];
spliti++;
srci+=2;
}
odd[spliti] = '\0';
spliti=0, srci=1; // even index starts with 1 in C
while (srci < size) {
even[spliti] = source[srci];
spliti++;
srci += 2;
}
even [spliti] = '\0';

Answer 3

There is a mistake in for loop in reachable function. For even you should start the loop at I=0 and increment by 2. For odd index you have to start the loop at i=1 and increment by 2. I think the code should be look like this:
for (i = 1; i<size; i+=2) {
odd[i] = source[i];
}
for (i = 0; i<size; i+=2) {
even[i] = source[i];
}