//upper case<=>lower case
#include<stdio.h>
#include<conio.h>
#include<string.h>
#include<iostream.h>
void uprtlwr(void);
void lwrtupr(void);
void main()
{
clrscr();
int chk;
	do
	{
	printf("\n Press 1 to change upper case to lower case:");
	printf("\n Press 2 to change lower case to upper case :");
	printf("\n Press 3 to EXIT:");
	printf("\n Please enter your choice......");
	scanf("%d",&chk);
	printf("\n");
	switch(chk)
		{
		case 1:
		uprtlwr();
		break;
		case 2:
		lwrtupr();
		break;
		case 3:
		break;
		default:
		printf("\n You have enter a wrong choice!!!!!!!!\n");
		break;
		}
	}
	while(chk!=3);
}
void uprtlwr(void)
{
printf("\n");
char nm[30],tmp;
int l,i;
printf("\n Enter your string in upper case:");
cin.getline(nm,'\30');
l=strlen(nm);
printf("\n Entered string in lower case is:");
for(i=0;i<l;i++)
{
if(nm[i]==32)
	{
	nm[i]=nm[i];
	}
else
nm[i]+=32;
printf("%c",nm[i]);
}
printf("\n");
getche();
}
void lwrtupr(void)
{
printf("\n");
char nm[30],tmp;
int l,i;
printf("\n Enter your string in lower case:");
cin.getline(nm,'\30');
l=strlen(nm);
printf("\n Entered string in upper case is:");
for(i=0;i<l;i++)
{
if(nm[i]==32)
	{
	nm[i]=nm[i];
	}
else
nm[i]-=32;
printf("%c",nm[i]);
}
printf("\n");
getche();
}