# Top 15 Practical Exam C Language Program in Computer Science

• ## Write A C Program to find the sum of series S=1+2+3+….+n

### “Program:”

``````
#include<stdio.h>
int main() {
int n,i;
int sum=0;
printf(“Enter the n i.e. max values of series: “);
scanf(“%d”,&n);
sum = (n * (n + 1)) / 2;
printf(“Sum of the series: “);
for (i =1;i <= n;i++) {
if (i!=n)
{
printf(“%d + “,i);
else
printf(“%d = %d “,i,sum);
}
return 0;
}
``````

### “Output:”

``````
Enter the n i.e. max values of series: 5
````Sum of the series: 1 + 2 + 3 + 4 + 5 = 15 ````

## Write a C program to find the Reverse Number:

### “Program:”

``````
#include <stdio.h>
int main()
{
int n, reverse = 0, remainder;
printf(“Enter an integer: “);
scanf(“%d”, &n);
while (n != 0)
{
remainder = n % 10;
reverse = reverse * 10 + remainder;
n /= 10;
}
printf(“Reversed number = %d”, reverse);
return 0;
}
``````

### “Output:”

``````
Enter an integer: 2345
Reversed number = 5432
``````

## Write A CProgram to find Sum of Digit .

### “Program:”

``````
#include<stdio.h>
int main()
{
int n,sum=0,m;
printf(“Enter a number:”);
scanf(“%d”,&n);
while(n>0)
{
m=n%10;
sum=sum+m;
n=n/10;
}
printf(“Sum is=%d”,sum);
return 0;
}
``````

### “Output:”

``````
Enter a number:654
Sum is=15
Enter a number:123
Sum is=6
``````

## Write A Program to find Digit on not:

### “Program:”

``````
#include<stdio.h>
#include<conio.h>
int main()
{
char ch;
clrscr();
printf(“Enter chracter: “);
scanf(“%c”, &ch);
if(ch>=’0′ && ch<=’9′)
{
printf(“%c is DIGIT.”, ch);
}
else
{
printf(“%c is NOT DIGIT.”, ch);
}
getch();
return(0);
}
``````

### “Output:”

``````
Enter any character: 9 ↲
9 is DIGIT.
———-
Enter any character: G ↲
G is NOT DIGIT.
``````

## Write A  C Program to find  a Number prime on not:

### “Program:”

``````
#include <stdio.h>
int main()
{
int n, i, flag = 0;
printf(“Enter a positive integer: “);
scanf(“%d”, &n);
if (n == 0 || n == 1)
flag = 1;
for (i = 2; i <= n / 2; ++i)
{
if (n % i == 0) {
flag = 1;
break;
}
}
if (flag == 0)
printf(“%d is a prime number.”, n);
else
printf(“%d is not a prime number.”, n);
return 0;
}
``````

### “Output:”

``````
Enter a positive integer: 56
56 is not a prime number.
Enter a positive integer: 29
29 is a prime number.
``````

## Write a C program to find S= 1-2 + 3-4 + 5-6 +7-8+. . . .+n

### “Program:”

``````
#include <stdio.h>
int series_sum(int n)
{
if (n % 2 == 0)
return (-(n/ 2));
else
return ((n + 1) / 2);
}
int main()
{
int n;
printf(“Series: 1-2+3-4+5-6+7-8…..N\n”);
printf(“Enter the N term value in Integer:”);
scanf(“%d”, &n);
printf(“Sum is: %d”, series_sum(n));
return 0;
}
``````

### “Output:”

``````
Series: 1-2+3-4+5-6+7-8…..N
Want some up to N terms?
Enter the N term:20
Sum is: -1
``````

## Write A  C Program Swap with macro:

### “Program:”

``````
#include <stdio.h>
int a,b,t;
int main()
{
printf(“Enter a The Number of a “);
scanf(“%d”, &a);
printf(“Enter The Number of b “);
scanf(“%d”, &b);
t=a;
a=b;
b=t;
printf(“After  swapping   value:\n a= %d \t b=%d “,a,b);
return 0;
}
``````

### “Output:”

``````
Enter a The Number of a 15
Enter The Number of b 20
After  swapping   value:
a= 20    b=15
``````

## Write a C Program to print a triangle of stars as follows (take a number of lines from users).

### “Program:”

``````
#include <stdio.h>
int main() {
int i, space, rows, k = 0;
printf(“Enter the number of rows: “);
scanf(“%d”, &rows);
for (i = 1; i <= rows; ++i, k = 0) {
for (space = 1; space <= rows – i; ++space) {
printf(”  “);
}
while (k != 2 * i – 1) {
printf(“* “);
++k;
}
printf(“\n”);
}
return 0;
}
``````

## Write a C Program to check the factor of a number.

### “Program:”

``````
#include <stdio.h>
int main()
{
int num, i;
printf(“Enter a positive integer: “);
scanf(“%d”, &num);
printf(“Factors of %d are: “, num);
for (i = 1; i <= num; ++i)
{
if (num % i == 0)
{
printf(“%d “, i);
}
}
return 0;
}
``````

### “Output:”

``````
Enter a positive integer: 50
Factors of 50 are: 1 2 5 10 25 50
``````

## Write a c Program to calculate the factorial of a number using a recursive function.

### “Program:”

``````
#include<stdio.h>
long factorial(int n)
{
if (n == 0)
return 1;
else
return(n * factorial(n-1));
}

void main()
{
int number;
long fact;
printf(“Enter a number: “);
scanf(“%d”, &number);
fact = factorial(number);
printf(“Factorial of %d is %ld\n”, number, fact);
return 0;
}

``````

### “Output:”

``````
Enter a number: 8
Factorial of 8 is 40320
``````

## Write a C Program to find the Maximum and minimum element of array.

### “Program:”

``````
#include <stdio.h>
void main()
{
int arr1[100];
int i, mx, mn, n;
printf(“Enter How Many Number In The Array :”);
scanf(“%d”,&n);
printf(“Input %d elements in the array :\n”,n);
for(i=1;i<n;i++)
{
printf(“Enter The Number %d: “,i);
scanf(“%d”,&arr1[i]);
}
mx = arr1[0];
mn = arr1[0];
for(i=1; i<n; i++)
{
if(arr1[i]>mx)
{
mx = arr1[i];
}
if(arr1[i]<mn)
{
mn = arr1[i];
}
}
printf(“Maximum element is : %d\n”, mx);
printf(“Minimum element is : %d\n\n”, mn);
}
``````

### “Output:”

``````
Enter How Many Number In The Array :5
Input 5 elements in the array :
element – 0 : 20
element – 1 : 22
element – 2 : 23
element – 3 : 25
element – 4 : 56
Maximum element is : 56
Minimum element is : 20
``````

## Write a c Program to find odd and even numbers of an array.

### “Program:”

``````
#include <stdio.h>
void main()
{
int n;
printf(“Enter number of elements in the array: “);
scanf(“%d”, &n);
int arr[n];
printf(“Enter %d elements in the array: “,n);
for(int i=0;i<n;i++)
{
scanf(“%d”,&arr[i]);
}
printf(“Even numbers in the array are: “);
for(int i=0;i<n;i++)
{
if(arr[i]%2==0)
printf(“%d “, arr[i]);
}
printf(“\nOdd numbers in the array are: “);
for(int i=0;i<n;i++)
{
if(arr[i]%2==1)
printf(“%d “, arr[i]);
}
}
``````

### “Output:”

``````
Enter the number of elements in the array: 4
Enter 4 elements in the array: 8 9 6 5
Even numbers in the array are: 8 6
Odd numbers in the array are: 9 5
``````

## Write a Program to Display the Fibonacci series in C Language.

### “Program:”

``````
#include <stdio.h>
int main()
{
int i, n;
int t1 = 0, t2 = 1
int nextTerm = t1 + t2;
printf(“Enter the number of terms: “);
scanf(“%d”, &n);
printf(“Fibonacci Series: %d, %d, “, t1, t2);
for (i = 3; i <= n; ++i)
{
printf(“%d, “, nextTerm);
t1 = t2;
t2 = nextTerm;
nextTerm = t1 + t2;
}
return 0;
}
``````

### “Output:”

``````
Enter the number of terms: 9
Fibonacci Series: 0, 1, 1, 2, 3, 5, 8, 13, 21,
``````