To calculate sum of digits

//Program made by Puneet Sharma
#include
#include
//To calculate sum of digits
int sum( int k)
{ if (k<10) return k;
else return ( ( k%10) + sum( k/10) ) ;
}
void main()
{
int i,j; char src[20],find [20] , ch;
clrscr();
printf("Enbter number " ); scanf("%d" , &i);
j = sum(i);
printf( "Sum is : %d ", j);
getch();
}

To toggle character

//program made by Puneet Sharma
#include
#include
//To toggle character
char toggle(char);
void main()
{
char arr[16];
int c,i; char a;
clrscr();
scanf("%s" , arr);
for(i=0;arr[i]!='\0';i++)
{
a= toggle(arr[i]) ;
printf("%c",a);
}
}
char toggle(char c)
{
if(c>=65 && c<=122)
{
if(c>=97)
return(c-32);
else
return(c+32);
}
}

Factorial

//Program made by Puneet Sharma
#include
#include
//To calculate factorial of a no
int factorial (int i )
{
if (i==1)return 1 ;
else return( i* factorial(i-1)) ;
}
int sumdigit(int i )
{
if (i<=0) return 0 ; else return( i%10 + sumdigit(i/10) ) ; } void main() { printf("\n%d " , factorial(5) ) ; printf("\n%d " , sumdigit(31564) ) ; getch(); }

Reverse Three digit no.

//Program made by Puneet Sharma
#include < stdio.h >
#include < conio.h >
//reverse three digit no
void main()
{
int a,b,r;
clrscr();
printf("Enter 3 digit no=");
scanf("%d",&a);
r=a%10;
b=r*100;
a=a/10;
r=a%10;
b=b+r*10;
a=a/10;
b=b+a;
printf("Result is %d",b);
getch();
}