/*
Project InsertString

Function to insert a substring into a string

Version 1.0 / 2002.04.01
Autor: pstrainer@gmx.net
*/

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

#define line_maxlen 100
#define myversion 3		// valid options: {1,2}

void insert_string(char*,char*,int);

void main (void) {

	char mystring[line_maxlen];
	char insertstring[line_maxlen];
	int position,sl;

	printf("Projekt InsertString\n");

	sl=1;
	while (sl>0) {
		printf("\nGeben sie einen Text ein: ");
		gets(mystring);
		sl=strlen(mystring);
		if (sl) {
			printf("Einsetzen: ");
			gets(insertstring);
			printf("Nach Position: ");
			scanf("%d",&position);
			fflush(stdin);

			printf("Original-String: <%s>\n",mystring);

			insert_string(mystring,insertstring,position);

			printf("Ergebnis-String: <%s>\n",mystring);
		}
	}
}

// *************** Version 1 ********************
#if myversion==1

void insert_string (char *x,char *z, int p) {
/*
Funktion insert_string
Insert string z into string x at position p

Version 1.0 / 2002.04.01
This version realized with library functions:
Autor: Peter Schindler, pstrainer@gmx.net

Syntax:
	char mystring[...],insertstring[...];
	int position;
	... ...
	insert_string(mystring,insertstring,position);

Length: 
9 lines of code
*/
	char buffer [line_maxlen];

	if ((p>=0) && (p<=int(strlen(x)))) { // validity test
		strcpy( buffer, x+p);			// save end in buffer
		x[p]='\0';						// clip x
		strcat( x, z );					// copy dst to x
		strcat(x,buffer);				// copy end to x
	}
}

// *************** Version 2 ********************
#elif myversion==2

void insert_string (char *x,char *z, int p) {
/*
Funktion insert_string
Insert string z into string x at position p

Version 2.0 / 2002.04.01
This version realized without library functions (using only "strlen"):
Autor: Peter Schindler, pstrainer@gmx.net

Syntax:
	char mystring[...],insertstring[...];
	int position;
	... ...
	insert_string(mystring,insertstring,position);

Length: 
14 lines of code
*/
	char buffer [line_maxlen];
	int i,j;

	if ((p>=0) && (p<=int(strlen(x)))) { // validity test

		// save end in buffer
		i=p;j=0;						// strcopy (buffer,x+p)
		while(x[i]!='\0') {buffer[j++]=x[i++];}
		buffer[j++]='\0';				// terminate buffer

		// copy dst to x
		i=p;j=0;						// strcat(x,z);
		while(z[j]!='\0') {x[i++]=z[j++];}

		// copy end to x
		j=0;							// strcat(x,buffer);
		while (buffer[j]!='\0') {x[i++]=buffer[j++];}
		x[i]='\0';						// terminate string
	}
}

// *************** Version 3 ********************
#elif myversion==3

int my_strlen(char *);

void insert_string (char *x,char *z, int p) {
/*
Funktion insert_string
Insert string z into string x at position p

Version 3.0 / 2002.04.01
This version realized without library functions:
Autor: Peter Schindler, pstrainer@gmx.net

Syntax:
	char mystring[...],insertstring[...];
	int position;
	... ...
	insert_string(mystring,insertstring,position);

Length: 
16 lines of code
*/
	int i,j;

	if ((p>=0) && (p<=int(my_strlen(x)))) { // validity test

		i=my_strlen(x);					// shift end
		j=i+my_strlen(z);
		while (j>p) {x[j--]=x[i--];}

		i=p;							// insert
		j=0;
		while (z[j]!='\0') {x[i++]=z[j++];}
	}
}
int my_strlen(char *x) {
// calculate the length of a string.
// does the same as library function "strlen"
	int i=0;
	while (x[i]!='\0') {i++;}
	return i;
}

// *************** Version ? ********************
#else

void insert_string (char *x,char *z, int p) {
	printf("\n *** Illegal value for macro variable myversion ***\n\n");
}

#endif

/* ========== eof insert_string.cpp ========== */