Generate random students groups with some suspense...

group-generator.c

/**
 * Generate random students groups with some suspense...
 */
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>

int randint(int max) 
{
    return rand() % (max + 1);
}

int slow_print(char *str, unsigned int us) 
{
    for (size_t i = 0; i < strlen(str); i++) {
        printf("%c", str[i]);
        fflush(stdout);
        usleep(us);
    }
}

int main(int argc, char *argv[]) 
{
    char names[100][64] = {0};

    // Random Seed
    srand((argc > 2) ? atoi(argv[2]) : 0);    

    // Read students names    
    int count = 0;
    while (fgets(names[count], sizeof(names[0]), stdin) == names[count] && strlen(names[count]) > 1) {
        names[count][strcspn(names[count], "\n")] = 0;
        count++;
    }

    // Shuffle students
    for (int k = 0; k < count; k++) {
        int r = randint(count - 1);    
        strcpy(names[count + 1], names[k]);
        strcpy(names[k], names[r]);
        strcpy(names[r], names[count + 1]);
    }

    // Show lovely teams
    int group = (argc > 1) ? atoi(argv[1]) : 2;
    int delay = (argc > 3) ? atoi(argv[3]) : 100000;
    for (int k = 0; k < count; k++) {
        int r = k % group;
        if (r == 0) {
            printf("%d. ", 1 + k / group);
            slow_print(names[k], delay);
            printf("%s", k < count - 1 ? " ♡ " : "\n");
        } 
        else if (r == group - 1) {
            slow_print(names[k], delay);
            printf("\n");
        }
        else {
            slow_print(names[k], delay);
            printf("%s", k < count - 1 ? " ♡ " : "\n");
        }
    }
    printf("\n");
}