Solutions for Unable to Open include file stdio.h or conio.h in C Programming is just see the Menu Options and in which select Directories then change the Drive letter, ie if the include directories path is "C:\TC\INCLUDE" change C as D or E etc. If the software is copied from D or E etc can be tried. The same to do for  "C:\TC\LIB".
 Swapping of Two Numbers in C or C Program to Swap Two Numbers or C program to Swap two numbers without using a third variable    #include <stdio.h> #include <conio.h>  void main() {    int x, y, temp;    clrscr();    // to clear screen       printf("Enter the value of x and y\n");    scanf("%d%d", &x, &y);    printf("Before Swapping\nx = %d\ny = %d\n",x,y);    temp = x;    x    = y;    y    = temp;    /*       without using temp variable, this can be used    let x=4 and y=5    x = x + y ;   x=x+y => x=4+5 => x=9     y = x - y ;   y=x-y => y=9-5 => y=4  value changed    x = x - y ;   x=x-y => x=9-4 => x=5  value changed      */       printf("After Swapping\nx ...