how to create a string from an array of strings C - c

Question

I am learning about arrays and was wondering if someone can help me out. I have an array of strings and need to create a new string which is a concatenation of all the array elements. The problem I'm having is I'm only able to print the first string in my array, not all of them. I understand there is a null at the end of each string in my array so how would I work around that issue? Maybe 2d array? By the way I'm not allowed to use any string manipulation functions from string.h. Thank you.
#include <stdio.h>
#include <stdlib.h>
int findLength(char array[])
{
int i = 0;
for (i = 0; array[i] != '\0'; i++)
{
}
return i;
}
void arrayToString(char string[])
{
int n = 0;
int i = 0;
int l = findLength(string);
char *finalString;
finalString = malloc(l * sizeof(char));
for (i = 0; string[i] != '\0'; i++) {
finalString[n] = string[i];
n++;
}
for (i = 0; finalString[i] != '\0'; i++) {
printf("%c", finalString[i]);
}
}
int main(int argc, const char * argv[])
{
char *color[] = { "red", "blue", "red" };
arrayToString(*color);
return 0;
}

Answer 1

Change your function arrayToString to have two arguments.one of type char ** and the second of type size_t defining the number of strings.Also let its return value to be char * to return a pointer to the allocated memory.finally don't forget to free this memory.
#include <stdio.h>
#include <stdlib.h>
int findLength(char array[]) {
int i = 0;
for (i = 0; array[i] != '\0'; i++) {
}
return i;
}
char* arrayToString(char **string, size_t size) {
int bigSize = 0, len;
int i = 0, j, k;
for (j = 0; j < size; j++) {
bigSize += findLength(string[j]);
}
char *bigstring = (char *)malloc(bigSize + 1);
for (j = 0; j < size; j++) {
len = findLength(string[j]);
for (k = 0; k < len; k++) {
bigstring[i++] = string[j][k];
}
}
bigstring[i] = '\0';
return bigstring;
}
int main(int argc, const char * argv[])
{
char *color[] = { "red", "blue", "red" };
char *bigstring = arrayToString(color, 3);
printf("%s\n", bigstring);
free(bigstring);
return 0;
}

Answer 2

you have several problems in your code, here is the fixed version with comments:
size_t findLength(char* array[]) {
size_t l = 0;
while (char *t = *array++)
while (*t++)
l++;
return l;
}
void copyAll(char* array[], char* out) {
while (char *t = *array++)
while (*t)
*out++ = *t++; // copy every symbol from every line into out string
*out = '\0'; // append last null-terminator
}
void arrayToString(char* array[]) {
char* finalString = malloc((findLength(array) + 1) * sizeof(char)); // allocate + 1 symbol for null terminator
copyAll(array, finalString);
printf("%s", finalString);
free(finalString); // don't forget to release memory
}
int main(int argc, char* argv[]) {
char* color[] = { "red", "blue", "red", 0 }; // you should add array terminator as well
arrayToString(color);
return 0;
}