/*Toggle-Case : If lower-case character entered, then change to upper-case and vice-verse :*/
Code:
#include<stdio.h>
#include<conio.h>
#include<ctype.h>
void main()
{
clrscr();
int a,b;
char ch;
do
{
printf("\n\n Enter any alphabet : ");
a=getchar();
if(a>=65&&a<=90)
{
b=tolower(a);
printf("\n\n The lower-case for %c is : %c ",a,b);
}
else if(a>=97&&a<=122)
{
b=toupper(a);
printf("\n\n The upper-case for %c is : %c ",a,b);
}
else
printf("\n\n Wrong Input..!!! Alphabet ONLY ");
printf("\n\n Do you want to continue ? (y/n) : ");
ch=getche();
}while(ch=='y'||ch=='Y');
getch();
}