/* FILE: fn-test.cpp
 * example of an interactive test-driver for a string function
 * this example shows how to test a string function, del_n
 *
 * warning: do not write a test-driver that reads both strings and 
 * ints from the keyboard, as it requires consuming the NEWLINE used
 * to enter an int from the keyboard. Instead, handcode the int
 * value used by your program, as shown in this example.
 */
   
#include <iostream.h>
#include <string.h>      // for strlen, strcpy, strchr, etc.

void del_n(char str[], int n);

const int N = 3;         // no. of chars to delete from string s

/* main() ------------------------------------------------
 */
void main(){

  char s[80];   //input string to test del_n

  //prompt and read s
  cout << "\nEnter s: ";
  cin.getline(s, 80);

  //driver loop
  while(cin){
    cout << endl << "s, len  before delete: " << endl << s 
	 << endl << strlen(s);
    del_n(s, N);
    cout << endl << "s, len after delete: " <<  endl << s 
	 << endl << strlen(s);

    // prompt and read s
    cout << "\nEnter s: ";
    cin.getline(s, 80);
  }
}

/* del_n() -------------------------------------------
 * deletes first n chars from str
 * PRE: strlen(str) > 0
 */
void del_n(char str[], int n){
     strcpy(str, &str[n]);  
}