How to run a unix command from a C program

The C function used to run the command is

system();

for eg:
system("ls");
execute ls command whereas

system("pwd");
execute pwd command.

A sample C program

#include<stdio.h>

#include<stdlib.h>

main()

    {

    char c[10]="pwd";

    system(c);

    }

It produces the output as

'pwd' is a unix command for showing the present working directory.