#include <stdio.h>
#include <stdlib.h>

//_________________________________________________________________ globals
char mystring[100]="";
char myfile[]="c:\\Users\\Public\\Documents\\test.txt";
FILE *fp;

//_________________________________________________________________ my functions ( methods )
void getString()
{
    printf("Input the string  (max 100 char): ");
    fgets(mystring, sizeof mystring, stdin);
    printf("The string you entered is : %s\n", mystring);
}

void saveString()
{
    fp=fopen(myfile, "a");  // create or append at end
    printf("save to file %s\n",myfile);
    fprintf(fp,mystring);
}

//_________________________________________________________________ main
int main()
{
    printf("try to get a string from keyboard and write it to the end of a file (append)!\n");

    getString();
    saveString();

    return 0;
}