Roman Numbers upto 100

//print Equivalent Roman number up to 100
#include<stdio.h>
int main()
{
int i,d=1,r,nn,b,q,c=0,flagx=1;
int n,candisplay=1;
clrscr();
printf("Enter the number:");
scanf("%d",&n);
q=n%10;
nn=n-q;
while(nn!=0)
{
nn=nn-10;
c++;
}
if(n>100)
printf(" Sorry Cannot display Roman number");
else
{
if(c==4)
{
printf("XL");
flagx=0;
}
 else if(c>=5 &&c<=8)
 {
 c=0;
 flagx=1;
 printf("L");
 q=(n-50)%10;
 nn=(n-50)-q;
 while(nn!=0)
 {
 nn=nn-10;
c++;
}

}
else if(c==9)
{
printf("XC");
flagx=0;
}
else if(c==10)
{
printf("C");
flagx=0;
}

 if(flagx==1)
{
for(i=0;i<c;i++)
{
 printf("X");
}    }

switch(q)
{
case 1:
printf("I");
break;
case 2 :
printf("II");
break;
case 3:
printf("III");
break;
case 4:
printf("IV");
break;
case 5:
printf("V");
break;
case 6:
printf("VI");
break;
case 7:
printf("VII");
break;
case 8:
printf("VIII");
break;
case 9:
printf("IX");
break;
}
}

printf("\n");
getch();
}

function to input and display student data

int getroll();
float getmark();

void display(char *,int,float);

void display(char *n,int ro,float m1)
{
printf("---------------------------------------------------\n");
printf("%20s%10s%15s\n","NAME","Roll NO","MARKS");
printf("---------------------------------------------------\n");
printf("%20s" ,n);
printf("%10d",ro);
printf("%15.2f",m1);

}
void main()
{
char *name="Hello",ch='u';
int roll;
float marks;
clrscr();
do
{
printf("Enter the name:");
scanf(" %s",name);
roll=getroll();

marks=getmark();
display(name,roll,marks);
printf("\nDo u want to continue? ");

printf("CH: %c",ch);
scanf(" %c",&ch);
printf("CH: %c",ch);

}while(ch!='n');
getch();

}

int  getroll()
{
int r;
printf("enter the roll number :");
scanf("%d",&r);
return r;

}

float getmark()
{

float m;
printf("enter the marks");
scanf("%f",&m);
return m;

}

Prime number using function

//prime number using function
#include<stdio.h>
int prime(int);
int main()
{
int num,val;
clrscr();
printf("Enter the number:");
scanf("%d",&num);
val=prime(num);

if(val==0)
printf("\nNumber is not prime\n");
else
printf("\nNumber is prime\n");
getch();
}
int prime(int a)
{

int i,count=0;
for(i=2;i<a/2;i++)
{
if((a%i)==0)
{
break;
}
else
count++;
}
if(count>0)
return 1;
else
return 0;
}

Factorial using for loop

//Factorial
#include<stdio.h>
int main()
{
float f;
int a,b,fact=1,i;
printf("Enter the number :");
scanf("%d",&a);
for(i=2;i<=a;i++)
{
fact=fact*i;
}
printf("Factorial is: %d",fact);
}

Sum of digits

//Sum of digits
#include<stdio.h>
#include<math.h>
main()
{
int num,sum=0,digit;
printf("enter the num");
scanf("%d",&num);
x:while(num!=0)
{
digit=num%10;
num=num/10;
sum=sum+digit;
}
if(sum>9)
{
num=sum;
sum=0;
goto x;
}
printf("sum=%d",sum);
}