### Some Basic Examples of C Programming: Part 1

// print "hello world"

#include <stdio.h>
#include <conio.h>

main ()

{
printf("Hello World");
getch ();
}
----------------------------------------------------------

// conversion between ferhenheit and celcius scale

#include <stdio.h>
#include <conio.h>
main ()
{float c,f;
printf("Enter the value of f=");
scanf("%f",&f);
c=((f-32)/1.8);
printf("The value of c is %f",c);
getch ();
}
-----------------------------------------------------------

// calculation of the area of a circle

#include <stdio.h>
#include <conio.h>
main ()
{float A,R,Z;
Z=3.1416;
printf("Enter the value of R");
scanf("%f",&R);
A=(Z*R*R);
printf("The value of area is %f",A);
getch ();
}
----------------------------------------------------------

// application of if-else to get the solutions of an quadratic equation

#include <stdio.h>
#include <conio.h>
#include <math.h>

main ()
{
float a,b,c,d,root1,root2;
printf("Enter the Values of a,b and c\n");
printf("Enter the Value of a\n\n");
scanf("%f",&a);
printf("\nEnter the Value of b\n\n");
scanf("%f",&b);
printf("\nEnter the Value of c\n\n");
scanf("%f",&c);
//scanf("%f%f%f",&a,&b,&c);
d=((b*b)-(4*a*c));
if(d<0)
{printf("The Roots are Imaginary");}
else
{
root1=(-b+sqrt(d))/(2*a);
root2=(-b-sqrt(d))/(2*a);
printf("\nroot1=%f \n\nroot2=%f",root1,root2);
}
getch ();
}
----------------------------------------------------------

// comparison of a number

#include <stdio.h>
#include <conio.h>
main ()
{
int no;

printf("\n Enter Number :");
scanf("%d",&no);
if(no>0)
{
printf("\n\n Number is greater than 0 !");
}
else
{
if(no==0)
{
printf("\n\n It is 0 !");
}
else
{
printf("Number is less than 0 !");
}
}
getch();
}
-----------------------------------------------------------

// program to show the grade of a subject

#include <stdio.h>
#include <conio.h>
#include <math.h>

main ()
{
float x;
printf("Enter the Value of x\n");
scanf("%f",&x);
if(x>=80 && x<=100)
{printf("A+");}
else if(x>=75 && x<80)
{printf("A-");}
else if(x>=70 && x<75)
{printf("A");}
else if(x>=65 && x<70)
{printf("B+");}
else if(x>=60 && x<65)
{printf("B");}
else if(x>=55 && x<60)
{printf("B-");}
else if(x>=50 && x<55)
{printf("C+");}
else if(x>=45 && x<50)
{printf("C");}
else if(x>=40 && x<45)
{printf("D");}
else if(x<40)
{printf("F");}
else if (x>100)
{printf("Please Enter the Value within 0 to 100");}
getch ();}
-----------------------------------------------------------

// application of switch in determining values from several equations

#include <stdio.h>
#include <conio.h>
#include <math.h>

main ()
{
int flag;
float x,y;
printf("Enter flag");
scanf("%d",&flag);
printf("Enter the value of x");
scanf("%f",&x);

switch(flag)
{
case -1:
y=(x*x);
printf("The value of y is %f",y);
break;

case 0:
y=sqrt(x);
printf("The value of y is %f",y);
break;

case 1:
y=x;
printf("The value of y is %f",y);
break;

case 2:

case 3:
y=2*(x-1);
printf("The value of y is %f",y);
break;

default:
y=0;
printf("The value of y is %f",y);}

getch ();}
----------------------------------------------------------

// application of switch to choice colors

#include <stdio.h>
#include <conio.h>
#include <ctype.h>

main ()
{
char choice;

switch(choice=toupper(getchar()))
{
case 'r':
printf("RED");
break;

case 'w':
printf("WHITE");
break;

case 'b':
printf("BLUE");
break;

default:
printf("Error");
}
getch ();
}
------------------------------------------------------------

// application of switch as well as if-else

#include <stdio.h>
#include <conio.h>
#include <math.h>

main ()
{

printf("enter in two numbers -->");
scanf("%d %d", &numb1, &numb2);
printf("enter in choice\n");
printf("2=subtraction\n");
{
case 1:
total = numb1 + numb2;
break;
case 2:
total = numb1 - numb2;
break;

default:
printf("Invalid option selected\n");
}
{printf("%d",total);}
{printf("%d",total);}

getch ();
}
---------------------------------------------------------------

//program which will display the consecutive digits from 0 to 9 with one digit on each line using for statement

#include <stdio.h>
#include <conio.h>
#include <math.h>

main ()
{
int digit;
for (digit=0; digit<=9; ++digit)
{printf("%d\n",digit);}
getch ();
}
-----------------------------------------------------------------

//program which will display the consecutive digits from 0 to 9 with one digit on each line using while statement

#include <stdio.h>
#include <conio.h>
#include <math.h>

main ()
{
int digit=0;
while (digit<=9)
{printf("%d\n",digit);
++digit;}
getch ();}
-----------------------------------------------------------------

//program which will display the consecutive digits from 0 to 9 with one digit on each line using do-while statement

#include <stdio.h>
#include <conio.h>
#include <math.h>

main ()
{
int digit=0;
do {printf("%d\n",digit++);}
while (digit<=9);
getch ();}
------------------------------------------------------------------

//calculation of the sum of squares of all the integers between 1 and 10

#include <stdio.h>
#include <conio.h>
#include <math.h>

main ()
{
int n;
float sum;
sum=0;
n=1;
while(n<=10)
{
sum=sum+(n*n);
n=n+1;
}
printf("sum=%f\n",sum);
getch ();
}
--------------------------------------------------------------------

// averaging a list of numbers

#include <stdio.h>
#include <conio.h>
#include <math.h>

main ()
{
int n,count;
float x,average,sum=0;
printf("How many numbers?");
scanf("%d",&n);
for (count=1; count<=n; ++count)
{printf("x=");
scanf("%f",&x);
sum+=x;}
average=sum/n;
printf("\nThe average is %f\n",average);
getch ();}
----------------------------------------------------------------------

//repeated averaging of a list of numbers

#include <stdio.h>
#include <conio.h>
#include <math.h>

main ()
{
int n,count,loops,loopcount;
float x,average,sum;
printf("How many lists?");
scanf("%d",&loops);

for(loopcount=1; loopcount<=loops; ++loopcount)
{
sum=0;
printf("\nList number %d\nHow many numbers?",loopcount);
scanf("%d",&n);

for(count=1; count<=n; ++count)
{
printf("x=");
scanf("%f",&x);
sum+=x;}
average=sum/n;
printf("\nThe average is %f\n",average);
}
getch ();
}