### Check Prime or Not - C Program

Program:

#include<stdio.h>
//#include<conio.h>
#include<math.h>
main()
{
int n,i,flag=0;//clrscr();
printf("Enter the number:");
scanf("%d",&n);
if(n<=1)
printf("\nThe no is not prime");
else
{
for(i=2;i<=(n/2);i++)
{
if(n%i==0)
flag=1;
}

if (flag==0)
printf("%d is prime.\n",n);
else
printf("%d is not prime.\n",n);
}
//getch();
}
Output:
nn@linuxmint ~ \$ gcc c2.c
nn@linuxmint ~ \$ ./a.out
Enter the number:2
2 is prime.
nn@linuxmint ~ \$ ./a.out
Enter the number:5
5 is prime.
nn@linuxmint ~ \$ ./a.out
Enter the number:9
9 is not prime.
nn@linuxmint ~ \$

### Largest Among 3 Numbers - C Program

Program:
#include<stdio.h>
//#include<conio.h>
void main()
{
int a,b,c;
//clrscr();
printf("Enter the numbers:");
scanf("%d%d%d",&a,&b,&c);
if(a>b)
{    if(a>c)
printf("%d is largest among %d,%d,%d\n",a,a,b,c);
else
printf("%d is largest among %d,%d,%d\n",c,a,b,c);
}
else if(b>c)
printf("%d is largest among %d,%d,%d\n",b,a,b,c);
else
printf("%d is largest among %d,%d,%d\n",c,a,b,c);
//getch();
}

Output:
nn@linuxmint ~ \$ gcc cc4.c
nn@linuxmint ~ \$ ./a.out
Enter the numbers:5
3
2
5 is largest among 5,3,2nn@linuxmint ~ \$

### Change Case of The Letter - C Program

Program:
#include<stdio.h>
//#include<conio.h>
void main()
{
char c; //clrscr();
printf("\n\t***A PROGRAM TO CHANGE THE CASE OF THE CHARACTER***\n\n");
printf("Enter a character:");
scanf("%c",&c);
if(c<96)
{
printf("\nYou entered the upper case letter '%c' \n\tThe lower case is '%c'.\n",c,c+32);
}
else
{
printf("\nYou entered the lower case letter'%c' \n\tThe upper case is'%c'.\n",c,c-32);
}
//getch();
}

Output:
nn@linuxmint ~ \$ gcc CC3.c
nn@linuxmint ~ \$ ./a.out

***A PROGRAM TO CHANGE THE CASE OF THE CHARACTER***

Enter a character:a

You entered the lower case letter'a'
The upper case is'A'.
nn@linuxmint ~ \$

### Find ASCII Value of Characters - C Program

Program:
#include<stdio.h>
//#include<conio.h>
void main()
{
int b=0,i;
//clrscr();
printf("ascii values for different numbers:\n");
for(i=0;i<100;i++)
{
b=b+1;
printf("\t%d=%c",b,b);
if(b%5==0)
printf("\n");
}
//getch();
}

Output:
nn@linuxmint ~ \$ gcc cc2.c
nn@linuxmint ~ \$ ./a.out
ascii values for different numbers:
1=     2=     3=     4=     5=
6=     7=    8=      9=        10=

11=
12=
14=     15=    13=
16=     17=     18=     19=     20=
21=     22=     23=     24=     25=
26=     27=     28=     29=     30=
31=     32=     33=!    34="    35=#
36=\$    37=%    38=&    39='    40=(
41=)    42=*    43=+    44=,    45=-
46=.    47=/    48=0    49=1    50=2
51=3    52=4    53=5    54=6    55=7
56=8    57=9    58=:    59=;    60=<
61==    62=>    63=?    64=@    65=A
66=B    67=C    68=D    69=E    70=F
71=G    72=H    73=I    74=J    75=K
76=L    77=M    78=N    79=O    80=P
81=Q    82=R    83=S    84=T    85=U
86=V    87=W    88=X    89=Y    90=Z
91=[    92=\    93=]    94=^    95=_
96=`    97=a    98=b    99=c    100=d
nn@linuxmint ~ \$

### Temperature Conversion C to F & F to C - C Program

Program:
#include<stdio.h>
//#include<conio.h>
void main()
{
int d,e=248;float a,b,c;
//clrscr();
printf("\n\t\t***Temperature conversion program***\n");
n:
printf("\n\tWhat u want to do?\n\t\t1:Convert %cC to %cF\n\t\t2:convert %cF to %cC\n\t\t",e,e,e,e);
scanf("%d",&d);
if(d==1)
{
printf("Enter the temp in %cc\n",e);
scanf("%f",&a);
b=(1.8*a)+32;
printf("The temperature in %cF is:%f",e,b);
}
else if(d==2)
{
printf("Enter the temperature in %cF:\n",e);
scanf("%f",&a);
b=((0.5555555555555556)*(a-32));
printf("The temperature in %cC is:%f",e,b);
}
else
{
printf("\n\tWrong choice!\n\tenter either 1 or 2\n\n\n");
goto n;
}
//getch();
}

Output:
nn@linuxmint ~ \$ gcc cc1.c
nn@linuxmint ~ \$ ./a.out

***Temperature conversion program***

What u want to do?
1:Convert �C to �F
2:convert �F to �C
1
Enter the temp in �c
100
The temperature in �F is:212.000000nn@linuxmint ~ \$ ./a.out

***Temperature conversion program***

What u want to do?
1:Convert �C to �F
2:convert �F to �C
3

Wrong choice!
enter either 1 or 2

What u want to do?
1:Convert �C to �F
2:convert �F to �C
2
Enter the temperature in �F:
212
The temperature in �C is:100.000000
nn@linuxmint ~ \$