Revise paste Untitled

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

void wtf() {
    FILE *f = fopen("input.txt", "w");
    char c;
    while((c = getchar()) != EOF) {
        fputc(c, f);
    }
    fclose(f);
}
int main() {
//    wtf();
    FILE *vlez = fopen("input.txt", "r");
    char niza[200];
    
    while(fgets(niza, 100, vlez) != NULL) {
        int kolku_cifri = 0;
        char cifri[200];
        
        for(int i = 0; i < strlen(niza); i++) {
            if(isdigit(niza[i])) {
                cifri[kolku_cifri] = niza[i];
                kolku_cifri++;
            }
        }
        for(int i = 0; i < kolku_cifri; i++) {
            for(int j = i + 1; j < kolku_cifri; j++) {
                if(cifri[i] > cifri[j]) {
                    char pom = cifri[i];
                    cifri[i] = cifri[j];
                    cifri[j] = pom;
                }
            }
        }
        printf("%d", kolku_cifri);
        printf(":");
        for(int i = 0; i < kolku_cifri; i++) {
            printf("%c", cifri[i]);
        }
        printf("\n");
    }
    return 0;
}