$ whois c

C

first released in 1972 · by Dennis Ritchie

$ guessprog --inspect c

year: 1972
paradigm: procedural
family: c like
memory: manual
binding: static
safety: weak

C(7)

AUTHORS: Dennis Ritchie
HISTORY: Dennis Ritchie developed C at Bell Labs between 1971 and 1973 as the systems language for the young Unix operating system. It grew out of B, a language created by his colleague Ken Thompson, adding data types and structures that let it make good use of newer hardware. In 1973 the Unix kernel was largely rewritten in C, one of the first operating system kernels written in a high-level language. The 1978 book "The C Programming Language" by Brian Kernighan and Ritchie, known as "K&R", served as its de facto specification for years.
USAGE: One of the most widely used languages ever, and still among the most popular. It is the language of operating system kernels, embedded firmware, databases, language runtimes and much of the software infrastructure other languages are built on.
SEE ALSO: C on Wikipedia ↗

$ cat reverse.c

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

/* Reverse a string in place with two pointers */
static void reverse(char *s) {
    for (char *e = s + strlen(s) - 1; s < e; s++, e--) {
        char tmp = *s; *s = *e; *e = tmp;
    }
}

int main(void) {
    char word[] = "guessprog";
    reverse(word);
    printf("%s\n", word);
    return 0;
}