1)
#include <stdio.h>
#include <string.h>
int main()
{
    char s[80], p[4] = "app";
    char* token;
    fgets(s, 50, stdin);
    token = strtok(s, ",");
    while (token != NULL)
    {
        if (strncmp(token, p, 3) == 0)
            printf("%s\n", token);
        token = strtok(NULL, ",");
    }
}
------------------------------------------
2)
#include "string.h"
#include "istream"
int main () {
    char s[1000], p[10];
    int c = 0;
    fgets(s, 1000, stdin);
    fgets(p, 10, stdin);
    char *sl = strtok(s," ");
    int h = strlen(p) - 1;
    while (sl != NULL){
        if (strncmp(sl, p, h) == 0){
            c++;
        }
        sl = strtok(NULL," ");
    }
    printf("%d", c);
}
------------------------------------------------
3)
#include <stdlib.h>
#include <string.h>
#include <istream>
int srt(const void* a, const void* b) {
    char** surnameA = (char**)a;
    char** surnameB = (char**)b;
    return strcmp(*surnameA, *surnameB);
}
int main() {
    char name[100];
    char* name1[20];
    int c = 0;
    fgets(name, 100, stdin);
    char* tok = strtok(name, ", ");
    while (tok != NULL) {
        name1[c] = strdup(tok);
        c=c+1;
        tok = strtok(NULL, ", ");
    }
    qsort(name1, c, sizeof(char*), srt);
    printf("sort:\n");
    for (int i = 0; i < c; i++) {
        printf("%s\n", name1[i]);
        free(name1[i]);
    }
}