QUADRATIC EQUATION

/* Quadratic Equation*/

#include<stdio.h>
#include<conio.h>
#include<math.h>
void main()
{
int a,b,c,d;
float r1,r2,s;
printf("enter a,b,c");
scanf("%d%d%d",&a,&b,&c);
d=b*b-(4*a*c);
s=sqrt(d);
if(d>=0)
{
r1=(-b+s)/(2*a);
r2=(-b-s)/(2*a);
if(r1==r2)
{
printf("the roots are real and equal\n");
printf("the root is %5.3f\n",r1);
}
else
printf("the roots are real and distinct\n");
printf("the roots are %5.3f and %5.3f\n",r1,r2);
}
else
printf("imaginary roots\n");
}

SUM AND REVERSE OF A NUMBER

/*Sum And Reverse Of A Number*/

#include<stdio.h>
#include<conio.h>
void main()
{
int n,sum=0,rev=0,r;
printf("enter the number");
scanf("%d",&n);
while(n>0)
{
r=n%10;
rev=(rev*10)+r;
sum=sum+r;
n=n/10;
}
printf("sum is %d",sum);
printf("\n reverse is %d",rev);
getch();
}

FACTORIAL OF A NUMBER

/*Factorial Of A Number*/
#include<stdio.h>
#include<conio.h>
void main()
{
int n,fact=1,i=1;
printf("enter number");
scanf("%d",&n);
while(i<=n)
{
fact=fact*i;
i++;
}
printf("factorial is %d",fact);
getch();
}

ARITHMETIC OPERATIONS

/*Arithmetic Operations*/ 

#include<stdio.h>
#include<conio.h>
void main()
{
int a,b,c;
int ch;
printf("enter the numbers");
scanf("%d%d",&a,&b);
printf("enter your choice");
Printf("1.multiplication,2.division,3.addition,4.subtraction");
scanf("%d",&ch);
if(ch>0)
{
if(ch==1)
{
printf("product=%d",a*b);
}
else
if(ch==2)
{
printf("quotient=%d",a/b);
}
else
if(ch==3)
{
printf("sum=%d",a+b);
}
else
if(ch==4)
{
printf("diff=%d",a-b);
}
else
printf("Invalid choice");
getch();
}
}

AMICABLE NUMBERS

/*Amicable Numbers*/

#include<stdio.h>
#include<conio.h>
void main()
{
int i,r=0,sum=0,sum1=0,a,b,temp,temp1;
printf("Enter first number\n");
scanf("%d",&a);
printf("Enter second number\n");
scanf("%d",&b);
temp=a;
for(i=1;i<=a/2;i++)
{
r=a%i;
if(r==0)
sum+=i;
}
temp=b;
for(i=1;i<=b/2;i++)
{
r=b%i;
if(r==0
sum1+=i;
}
if((sum==temp1)&&(sum==temp))
printf("amicable");
else
printf("not amicable");
getch();
}

CHECK BALANCED EXPRESSION USING STACK

/* check balanced  expression using stack */

#include < stdio.h >

#include < conio.h >

#define max 50

void main()

{

                char stk[max],exp[100];

                int top,i;              

                clrscr();

                top = -1;              

                printf("\nEnter an infix expression ");

                gets(exp);          

                for(i=0; exp[i] != '\0'; i++)

                {

                                if( exp[i]=='(' || exp[i] =='[' || exp[i] == '{' )

                                {

                                                top++;

                                                stk[top]= exp[i];

                                }

                                else

                                if ( exp[i] == ')' )

                                {

                                                if( stk[top] == '(' )

                                                top--;

                                }

                                else

                                {

                                                printf("Unbalanced exp");

                                                exit(0);

                                }

                                }

                                else

                                if ( exp[i] == ']' )

                                {

                                if( stk[top] == '[' )

                                                top--;

                                else

                                {

                                                printf("Unbalanced exp");

                                                exit(0);

                                }

                                }

                                else

                                if ( exp[i] == '}' )

                                {

                                if( stk[top] == '{' )

                                                top--;

                                else

                                {

                                                printf("Unbalanced exp");

                                                exit(0);

                                }

                                }

                } // for

                if( top == -1 )

                                printf("Exp is balanced");

                else

                                printf("Exp is not balanced");

} 

AVERAGE OF N NUMBERS

/* Average Of N Numbers */

#include < stdio.h >

#include < conio.h >

void main()

{

                float a[20],sum,avg;

                int n,i;

                clrscr();

                printf("\nEnter n : ");

                scanf("%d", &n);

                printf("\nEnter %d numbers \n",n);

                for(i=0;i < n;i++)

                {

                   scanf("%f", &a[i]);

                }

                sum = 0;

                for(i=0;i < n;i++)

                {

                                sum += a[i];

                }

                avg = sum / n;

                printf("\nEntered %d numbers are \n",n);

                for(i=0;i < n;i++)

                {

                                printf("\n%.2f",a[i]);

                }

                printf("\nThe average of numbers is %f",avg);

}