palindrome numbers in a given range

```
#include<stdio.h>
#include<conio.h>
void main(){
int num, rem, reverse, temp, start, end;

printf("Enter the lower Number");
scanf("%d",&start);

printf("Enter the upper Number");
scanf("%d",&end);

printf("Palindrome numbers between %d and %d are: ",start,end);
for(num=start;num<=end;num++){
temp=num;
reverse=0;
while(temp){
rem=temp%10;
temp=temp/10;
reverse=reverse*10+rem;
}
if(num==reverse)
printf("%d ",num);
}
getch();
}
```

check Armstrong number

```

#include<stdio.h>
#include<conio.h>
void main()
{
int num,temp,sum=0,rem;

printf("\nEnter a number:");
scanf("%d",&num);

temp= num;

while (num != 0)
{
rem = num % 10;
sum = sum + (rem*rem*rem);
num = num / 10;
}

if(temp == sum)
printf("\n%d is an Armstrong Number",temp);
else
printf("\n%d is not an Armstrong Number",temp);
getch();
}```

Reverse number using Recursion

```

#include<stdio.h>
#include<conio.h>
void main()
{
int num,reverse_number;
printf("\nEnter any number:");
scanf("%d",&num);
reverse_number=reverse_function(num);
printf("\nAfter reverse the no is :%d",reverse_number);
getch();
}
int sum=0,rem;
reverse_function(int num){
if(num){
rem=num%10;
sum=sum*10+rem;
reverse_function(num/10);
}
else
return sum;
return sum;
}

```

Fibonacci Series

```#include<stdio.h>
#include<conio.h>
int main()
{
int count, first = 0, second = 1, next, i;

printf("Enter the number of terms:\n");
scanf("%d",&count);

printf("First %d terms of Fibonacci series:\n",count);
for ( i = 0 ; i < count ; i++ )
{
if ( i <= 1 )
next = i;
else
{
next = first + second;
first = second;
second = next;
}
printf("%d\n",next);
}

getch();
}```

Find ASCII value of a Character

```

#include<stdio.h>
#include<conio.h>
void main()
{
char ch;
printf("Enter any character:");
scanf("%c", &ch);
printf("ASCII value of character %c is: %d", ch, ch);
getch();
}```

check if a number is palindrome or not

```
#include<stdio.h>
#include<conio.h>
void main()
{
int num, reverse=0, remainder,temp;
printf("Enter an integer: ");
scanf("%d", &num);

temp=num;
while(temp!=0)
{
remainder=temp%10;
reverse=reverse*10+remainder;
temp/=10;
}

if(reverse==num)
printf("%d is a palindrome number",num);
else
printf("%d is not a palindrome number",num);
getch();
}```

find the size of data types in C

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

printf("Size of char: %ld byte\n",sizeof(char));
printf("Size of int: %ld bytes\n",sizeof(int));
printf("Size of float: %ld bytes\n",sizeof(float));
printf("Size of double: %ld bytes", sizeof(double));
getch();
}
```

check Leap Year

```#include<stdio.h>
#include<conio.h>
void main()
{
int y;

printf("Enter year: ");
scanf("%d",&y);

if(y % 4 == 0)
{

if( y % 100 == 0)
{
if ( y % 400 == 0)
printf("%d is a Leap Year", y);
else
printf("%d is not a Leap Year", y);
}
else
printf("%d is a Leap Year", y );
}
else
printf("%d is not a Leap Year", y);

getch();
}

```

convert uppercase string to lowercase string
```
#include<stdio.h>
#include<conio.h>
#include<string.h>
void main(){

char str[25];
int i;
printf("Enter the string: ");
scanf("%s",str);

for(i=0;i<=strlen(str);i++){
if(str[i]>=65&&str[i]<=90)
str[i]=str[i]+32;
}
printf("\nLower Case String is: %s",str);
getch();
}
```

convert lowercase string to uppercase

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

void main()
{
char str[25];
int i;

printf("Enter the string:");
scanf("%s",str);

for(i=0;i<=strlen(str);i++){
if(str[i]>=97&&str[i]<=122)
str[i]=str[i]-32;
}
printf("\nUpper Case String is: %s",str);
getch();
}
```

Sorting of a Set of Strings in Ascending alphabetical order

```#include<stdio.h>
#include<conio.h>
#include<string.h>
void main(){
int i,j,count;
char str[25][25],temp[25];
puts("How many strings u are going to enter ? ");
scanf("%d",&count);

puts("Enter Strings one by one ");
for(i=0;i<=count;i++)
gets(str[i]);
for(i=0;i<=count;i++)
for(j=i+1;j<=count;j++){
if(strcmp(str[i],str[j])>0){
strcpy(temp,str[i]);
strcpy(str[i],str[j]);
strcpy(str[j],temp);
}
}
printf("Order of Sorted Strings:");
for(i=0;i<=count;i++)
puts(str[i]);

getch();
}
```

find the length of a String without using function strlen()

```#include<stdio.h>
#include<conio.h>
#include <stdio.h>
void main()
{
char str[100],i;
printf("Enter a string: \n");
scanf("%s",str);
for(i=0; str[i]!='\0'; ++i);
printf("\nLength of input string: %d",i);

getch();
}
```

concatenate two strings without using strcat

```#include<stdio.h>
#include<conio.h>
#include<stdio.h&ht;
void main()
{
char str1[50], str2[50], i, j;
printf("\nEnter first string: ");
scanf("%s",str1);
printf("\nEnter second string: ");
scanf("%s",str2);

for(i=0; str1[i]!='\0'; ++i);

for(j=0; str2[j]!='\0'; ++j, ++i)
{
str1[i]=str2[j];
}
str1[i]='\0';
printf("\nOutput: %s",str1);

getch();
}
```

arrange numbers in ascending order

```#include<stdio.h>
#include<conio.h>
void sort_numbers_ascending(int number[], int count)
{
int temp, i, j, k;
for (j = 0; j < count; ++j)
{
for (k = j + 1; k < count; ++k)
{
if (number[j] > number[k])
{
temp = number[j];
number[j] = number[k];
number[k] = temp;
}
}
}
printf("Numbers in ascending order:\n");
for (i = 0; i < count; ++i)
printf("%d\n", number[i]);
}
void main()
{
int i, count, number[20];

printf("How many numbers you are gonna enter:");
scanf("%d", &count);
printf("\nEnter the numbers one by one:");

for (i = 0; i < count; ++i)
scanf("%d", &number[i]);

sort_numbers_ascending(number, count);
getch();
}
```

find largest element of an Array

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

int largest_element(int arr[], int num)
{
int i, max_element;
max_element = arr[0];
for (i = 1; i < num; i++)
if (arr[i] > max_element)
max_element = arr[i];

return max_element;
}

void main()
{
int arr[] = {1, 24, 145, 20, 8, -101, 300};
int n = sizeof(arr)/sizeof(arr[0]);
printf("Largest element of array is %d", largest_element(arr, n));
getch();
}```

display its own source code using __FILE__

```#include<stdio.h>
#include<conio.h>
void main() {
FILE *fp;
char c;
fp = fopen(Rain.c,"r");
do {
c = getc(fp);
putchar(c);
}
while(c != EOF);
fclose(fp);
getch();
}
```

Copy String Without Using strcpy()

```#include<stdio.h>
#include<conio.h>
void main()
{
char s1[100], s2[100], i;

printf("Enter string s1: ");
scanf("%s",s1);

for(i = 0; s1[i] != '\0'; ++i)
{
s2[i] = s1[i];
}

s2[i] = '\0';
printf("String s2: %s", s2);

getch();
}
```

Remove all Characters in a String Except Alphabet

```#include<stdio.h>
#include<conio.h>
void main()
{
char line[150];
int i, j;
printf("Enter a string: ");
gets(line);

for(i = 0; line[i] != '\0'; ++i)
{
while (!( (line[i] >= 'a' && line[i] <= 'z') || (line[i] >= 'A' && line[i] <= 'Z') || line[i] == '\0') )
{
for(j = i; line[j] != '\0'; ++j)
{
line[j] = line[j+1];
}
line[j] = '\0';
}
}
printf("Output String: ");
puts(line);
getch();
}
```

count the number of vowels, consonants and so on

```#include<stdio.h>
#include<conio.h>
int main()
{
char ch[150];
int i, vowels, consonants, digits, spaces;

vowels =  consonants = digits = spaces = 0;

printf("Enter a ch of string: ");
scanf("%[^\n]", ch);

for(i=0; ch[i]!='\0'; ++i)
{
if(ch[i]=='a' || ch[i]=='e' || ch[i]=='i' ||
ch[i]=='o' || ch[i]=='u' || ch[i]=='A' ||
ch[i]=='E' || ch[i]=='I' || ch[i]=='O' ||
ch[i]=='U')
{
++vowels;
}
else if((ch[i]>='a'&& ch[i]<='z') || (ch[i]>='A'&& ch[i]<='Z'))
{
++consonants;
}
else if(ch[i]>='0' && ch[i]<='9')
{
++digits;
}
else if (ch[i]==' ')
{
++spaces;
}
}

printf("Vowels: %d",vowels);
printf("\nConsonants: %d",consonants);
printf("\nDigits: %d",digits);
printf("\nWhite spaces: %d", spaces);

getch();
}
```

Factors of a Positive Integer

```#include<stdio.h>
#include<conio.h>
void main()
{
int x,i;

printf("Enter a positive integer: ");
scanf("%d",&x);

printf("Factors of %d are: ", x);
for(i=1; i <= x; ++i)
{
if (x%i == 0)
{
printf("%d ",i);
}
}

getch();
}
```

Count Number of Digits in an Integer

```#include<stdio.h>
#include<conio.h>
void main()
{
long long n;
int count = 0;

printf("Enter an integer: ");
scanf("%lld", &n);

while(n != 0)
{
// n = n/10
n /= 10;
++count;
}

printf("Number of digits: %d", count);
getch();
}
```

Check Whether a Character is an Alphabet or not

```#include<stdio.h>
#include<conio.h>
void main()
{
char c;
printf("Enter a character: ");
scanf("%c",&c);

if( (c>='a' && c<='z') || (c>='A' && c<='Z'))
printf("%c is an alphabet.",c);
else
printf("%c is not an alphabet.",c);

getch();
}
```