Unique character count function does not take into consideration all lines (C) - arrays

Question

My goal is to write a function, that calculates the number of all the unique characters from a redirected text file (meaning until EOF is reached). The code I wrote:
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#define ASCII_VALS 128
int strLen (char inp[])
{
int len = 0;
for(int i = 0; inp[i] != '\0'; i++){
len++;
}
return len;
}
int countUniqueChars (char inp[])
{
int everyCharValArr[ASCII_VALS] = {0};
int i, j = 0;
for(i = 0; i < strLen(inp); i++){
int convToInt = inp[i] - '0';
everyCharValArr[convToInt] = 1;
}
for (i = 0; i < ASCII_VALS; i++) {
j += everyCharValArr[i];
}
return j;
}
works for one string entered via scanf() like so:
int main ()
{
char inp[100];
printf("Enter a string: \n");
scanf("%99s", inp);
printf("%d\n", countUniqueChars(inp));
return 0;
}
But after I change the main function to read a redirected text file, like so:
int main ()
{
char inp[100];
int total = 0;
while(fgets(inp, 100, stdin)){
total += countUniqueChars(inp);
}
printf("%d\n", total);
return 0;
}
and runinng the program (./binary <input.txt) on a input.txt file with contents below:
Toydolls
Flies
trees
rocks
things
the value becomes 26, which is correct (1. word = 6 unique chars, 2. word = 5 unique chars, 3. word = 4 unique chars, 4. word = 5, 5. word = 6 unique chars), but it obviously does not take into consideration chars that appear on more lines, which should not be counted as unique chars at all. My question is How do I fix the function to accomplish this?

Answer 1

Try something like that: Note that I've added a mechanism not to count a duplicate uppercase letter and its lower case letter as unique.
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <ctype.h>
#define ASCII_VALS 128
int everyCharValArr[ASCII_VALS] = {0};
int strLen (char inp[])
{
int len = 0;
for(int i = 0; inp[i] != '\0'; i++){
len++;
}
return len;
}
void FindUniqueChars (char inp[])
{
int i;
for(i = 0; i < strLen(inp); i++){
if (inp[i] > ' ' && inp[i] != (char)127)
{
if (inp[i] >= 'A' && inp[i] <='Z')
{
inp[i] = tolower(inp[i]);
}
everyCharValArr[(int)inp[i]] = 1;
}
}
}
int CountUniqueChars( void )
{
int i, j = 0;
for (i = 0; i < ASCII_VALS; i++) {
j += everyCharValArr[i];
}
return j;
}
int main ()
{
char inp[100];
while(fgets(inp, 100, stdin)){
FindUniqueChars(inp);
}
printf("%d\n", CountUniqueChars());
return 0;
}