look and say sequence program not outputting correct sequence - c

Question

This program is taking input from a file named "input.txt" however it is not outputting the correct look and say sequence. The program should input 21 and 114421. The output should be 1211 and 21241211, however it is just giving me nonsense numbers.
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char *argv[]){
char input[1024]; //The input element
char result[1024]; //The next element
int length = 0; //The length of the input
int resultLength = 0; //The length of the result
FILE *openFile;
openFile = fopen("input.txt", "r");
do{
fgets(input, 1024, openFile);
} while((input[length++] != '.') && (!feof(openFile)));
length -= 1; //Decrement length because of the length++ that just executed
//Go through the loop, adding to the result each time the chain stops
fclose(openFile);
char prev = input[0]; //The previous character
int count = 1; //The count in the current chain
int i, j = 0;
for(i=1; i < length; i++){
if(input[i] == prev){
count++; //If the chain is unbroken, increment the count
} else{
//If the chain breaks, store the count and digit in result and reset count
result[j++] = count + '0';
result[j++] = prev;
count = 1;
}
//Set prev to be the current digit
prev = input[i];
}
//Handle the last digit using the current value of count and prev
result[j++] = count + '0';
result[j++] = prev;
//Print out the result
printf("The next element in the sequence is: ");
resultLength = j;
for(i=0; i < resultLength; i++){
printf("%c", result[i]);
}
printf("\n");
system("pause");
return 0;
}

Answer 1

fix like this
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(void){
char input[1024];
char result[2*sizeof(input)];
int length = 0;// The length of the input
FILE *openFile = fopen("input.txt", "r");
if(!openFile){
perror("fopen:");
exit(EXIT_FAILURE);
}
while(fgets(input, 1024, openFile)){
char *p = strchr(input, '\n');
if(!p){
fprintf(stderr, "Input too long!\n");
exit(EXIT_FAILURE);
}
*p = 0;//chomp newline
length = p - input;
if(*input == '.' && !input[1]){
puts("c u!");
return 0;
}
//conversion
int resultLength = 0;
int i, j;
for(i = 0; i < length; i = j){
int count = 1;
for(j = i + 1; input[i] == input[j]; ++j)
++count;//Count of repeated characters
while(count > 9){//Processing when the count exceeds 9 E.g 111111111111 ==> 9131
result[resultLength++] = '9';
result[resultLength++] = input[i];
count -= 9;
}
result[resultLength++] = count + '0';
result[resultLength++] = input[i];
}
result[resultLength] = 0;//Add NUL charancter to last for %s of printf
//Print out the result
printf("The next element in the sequence is: %s\n", result);
}
fclose(openFile);
return 0;
}