how to put a char into a string c

// C program to Append a Character to a String 
  
#include <stdio.h> 
#include <string.h> 
  
int main() 
{ 
    // declare and initialize string 
    char str[] = "Geek"; 
  
    // declare and initialize char 
    char ch = 's'; 
  
    // print string 
    printf("Original String: %s\n", str); 
    printf("Character to be appended: %c\n", ch); 
  
    // append ch to str 
    strncat(str, &ch, 1); 
  
    // print string 
    printf("Appended String: %s\n", str); 
  
    return 0; 
}