Question

In C given an text file such as this "input.txt "

122345543221
3215123
12341234
287823883288432
888898888
099878
099990

723847238949238
63276276
9812983932487
3456712332176543
83274828374

sort each line in digits 0-9 and remove repeating digits

for example 576839201 would be 0123456789

Answer 1

#include <stdio.h>
#include <stdlib.h>
void initializeArr(int arr[])
{
int i=0;
for(i=0;i<10;i++)
arr[i]=-1;
}
int main(void) {
int i=0,arr[10];
initializeArr(arr);
FILE *fp = fopen("input.txt", "r");
if(fp == NULL) {
perror("Unable to open file!");
exit(1);
}

char chunk[128];
int val;
while(fgets(chunk, sizeof(chunk), fp) != NULL) {
int length=strlen(chunk);
for(i=0;i<length;i++)
{
if(chunk[i]!='\n')
{
val=chunk[i]-48;
arr[val]=val;
}
}
for(i=0;i<10;i++)
{
if(arr[i]!=-1)
printf("%d",arr[i]);
}
printf("\n");
initializeArr(arr);
}

fclose(fp);
}

Output: