This utility is useful for cases where a really large number of files needs to be created, and the cost of loops in bash or some other shell is prohibitively high.

touch.c

#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>

int touch_file(const char *prefix, const char *suffix, size_t index) {
    char filename[1024] = {0};
    strncpy(filename, prefix, strlen(prefix));
    char *end = &filename[0] + strlen(prefix);
    int n = sprintf(end, "%zd", index);
    if (n < 0) {
        return -1;
    }
    end += n;
    sprintf(end, ".%s", suffix);
    mode_t touch_mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
    int fd = open(filename, O_RDWR | O_CREAT, touch_mode);
    if (fd < 0) {
        return fd;
    }
    return close(fd);
}

int main (int argc, char **argv) {
    int opt;
    char *prefix;
    char *suffix;
    long long nfiles = 0;
    while ((opt = getopt(argc, argv, "n:p:s:")) != -1) {
        switch (opt) {
        case 'n':
            nfiles = strtoll(optarg, NULL, 10);
            if (nfiles < 0) {
                nfiles = -nfiles;
            }
            break;
        case 'p':
            prefix = optarg;
            break;
        case 's':
            suffix = optarg;
            break;

        default: /* '?' */
            fprintf(stderr, "Usage: %s <-c nfiles> <-p prefix> <-s suffix>\n",
                    argv[0]);
            exit(EXIT_FAILURE);
        }
    }

    for (size_t i = 0; i < (size_t)nfiles; i++) {
        int ret = 0;
        if ((ret = touch_file(prefix, suffix, i)) < 0) {
            fprintf(stderr, "touch_file returned: %d\n", ret);
            perror("touch_file");
            exit(EXIT_FAILURE);
        }
    }
}