1. Write a program to read two numbers and find sum

#include<stdio.h>
#include<stdio.h>
void main( )
{
      int Fno,Sno,sum;
      clrscr();
      printf("Enter Two Numbers : ");
      scanf("%d%d",&Fno,&Sno);
      sum=Fno+sno;
      printf("Sum=%d",sum);
}

2. Write a program to find the area and circumference of a Circle

#include<stdio.h>
#include<conio.h>
void main( )
{

float radius,area,circum;

clrscr();

printf("Enter the Radius : ");

scanf("%f",&radius);

area=3.14*r*r;

circum=2*3.14*r;

printf("Area=%f\n",area);

printf("Circumference=%f",circum);

3. Write a program to read two numbers and do all the arithmetic operations on it.

#include<stdio.h>
#include<conio.h>
void main( )
{
      int Fno,Sno,sum,diff,product;
      float quotient;
      clrscr();
      printf("Enter Two Numbers : ");
      scanf("%d%d",&Fno,&Sno);
      sum=Fno+sno;
      diff=Fno-Sno;
      product=Fno*Sno;
      Quotient=(float)Fno/Sno;
      printf("%d+%d=%d\n",Fno,Sno,sum);
      printf("%d-%d=%d\n",Fno,Sno,diff);
      printf("%d*%d=%d\n",Fno,Sno,product);
      printf("%d/%d=%f",Fno,Sno,quotient);
}

4. Write a program to read numbers into two variables and interchange their values using a third variable.

#include<stdio.h>
#include<conio.h>
void main( )
{
      int a,b,c;
      clrscr();
      printf("Enter two numbers :");
      scanf("%d%d",&a,&b);
      printf("\nBefore Swapping\n");
      printf("a=%d\nb=%d\n",a,b);
      c=a;
      a=b;
      b=c;
      printf("\nAfter Swapping\n");
      printf("a=%d\nb=%d\n",a,b);
}

5. Write a program to read numbers into two variables and interchange their values without using a third variable.

#include<stdio.h>
#include<conio.h>
void main( )
{
      int a,b,c;
      clrscr();
      printf("Enter two numbers :");
      scanf("%d%d",&a,&b);
      printf("\nBefore Swapping\n");
      printf("a=%d\nb=%d\n",a,b);
      a=a+b;
      b=a-b;
      a=a-b;
      printf("\nAfter Swapping\n");
      printf("a=%d\nb=%d\n",a,b);
}