Here is example of a C program that uses a for loop to calculate the sum of 'n' numbers:

In this program, first, the user is prompted to enter the value of 'n' (the number of numbers to be added). Then, a for loop is used to iterate 'n' times and prompt the user to enter a number in each iteration. The variable 'sum' is initialized to 0 and it's being used to keep the sum of all numbers entered by the user. In each iteration, the value of 'num' is added to 'sum' using the += operator. Finally, the program prints the sum of 'n' numbers.

In this example, the for loop starts with i=1, and it will run as long as i <= n, with i being incremented by 1 in each iteration.

It's important to note that, if you want to input the n numbers at once, you can use an array and use a for loop to iterate over the array and add the numbers to the sum variable.

This C program uses a for loop to calculate the sum of 'n' numbers by prompting the user to enter a number in each iteration of the loop, adding it to a running sum, and finally printing the total sum at the end. This is a simple and efficient way to calculate the sum of multiple numbers.

 C program for addition, subtraction, multiplication and division using switch

• the user is prompted to enter two numbers and then a choice for the operation to be performed. The choice is taken as an integer input and is used in the switch statement. 
• Depending on the user's choice, the program performs the corresponding operation using the two numbers as input.
• It's worth noting that, in the division operation, if the second number is zero, it will cause a runtime error because division by zero is not defined. 
• I have used type casting to convert the int variables to float so as to get the decimal value. Also, I have used the format specifier %.2f to print the result with 2 decimal places.
• the user is prompted to enter two numbers and then a choice for the operation to be performed. The choice is taken as an integer input using the scanf function and is used in the switch statement. Depending on the user's choice, the program performs the corresponding operation using the two numbers as input.
• you can try same program try to practice this using function:  c program for addition subtraction, multiplication and division using function

• The switch statement checks for the value of the variable choice. Depending on the value, the program enters the corresponding case and performs the operation. The break statement is used at the end of each case to exit the switch statement and prevent the program from executing the next case.
• In the case of the division operation, I have used type casting to convert the int variables to float so as to get the decimal value. Also, I have used the format specifier %.2f to print the result with 2 decimal places.
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• In the default case, if the user enters any value other than 1, 2, 3, or 4, the program displays an "Invalid choice!" message. This is to handle the scenario when the user enters an unexpected value.

 c program for addition subtraction, multiplication and division using function

• In this program, four functions are defined for addition, subtraction, multiplication, and division respectively. Each function takes two integer arguments a and b, performs the corresponding operation, and returns the result. 
• In the main function, variables a and b are initialized with the values 10 and 5 respectively.
• The functions are called and the results are stored in variables add_result, subtract_result, multiply_result, and divide_result. 
• These functions take two integer arguments and return the result of the operation. In the main() function, two integers are taken as input, and then the functions are called with these inputs to perform the operations and display the results.
• In the division operation, if the second number is zero, it will cause a runtime error because division by zero is not defined. 
• It's also important to consider the case where the division operation results in decimal values, In that case, you should use float or double instead of int.

 In C, you can use the int data type to represent ASCII values. Each character in the ASCII table is assigned a unique number between 0 and 127. To get the ASCII value of a character, you can simply cast it to an int. Here's an example:

char c = 'A';

int asciiValue = (int)c;

printf("The ASCII value of '%c' is %d\n", c, asciiValue);

This will output:

The ASCII value of 'A' is 65

Alternatively you can also use the 'C' library function (int)c to get the ASCII value of a character.

char c = 'A';

int asciiValue = (int)c;

printf("The ASCII value of '%c' is %d\n", c, asciiValue);

will give you the same output.

You can also find the ASCII value of a character with a function like getchar(), that returns an int value of the char type that it reads from the keyboard, or with a function like scanf() that reads a character input.

Additionally, if you want to find the ASCII value of a string, you can use a for loop to iterate through each character of the string and then get the ASCII value of each character by casting it to an int.

#include <stdio.h>

int main() {

    int i;

The first line includes the standard input/output header file, which is needed for the printf function used later in the program.

The main function is the entry point for the program. It is the first function that is executed when the program runs.

The next line declares a variable i of type int. This variable will be used as the loop counter in the for loop.

    for (i = 1; i <= 10; i++) {

        printf("2 * %d = %d\n", i, 2 * i);

    }

This is the for loop. It starts with the for keyword, followed by parentheses that contain three statements separated by semicolons:

The initialization statement i = 1 sets the value of i to 1 before the loop starts.

The loop condition i <= 10 specifies that the loop will continue as long as the value of i is less than or equal to 10.

The iteration statement i++ increments the value of i by 1 after each iteration of the loop.

Inside the loop, the printf function is used to print a string to the console. The string contains two %d format specifiers, which are placeholders for two integer values that will be printed. The first %d is replaced by the value of i, and the second %d is replaced by the result of 2 * i. The \n at the end of the string is a newline character that causes the output to be printed on a new line.

Finally, the return 0; statement at the end of the main function indicates that the program has completed successfully.

C program that finds the largest element in an array :

• This program first reads in n, the number of elements in the array. It then reads in n elements from the user and stores them in the array. 
• Finally, it iterates through the array and compares each element to the first element (which is initially set to the largest). 
• If it finds a larger element, it updates the value of the first element to be the larger value. At the end, the program prints out the largest element in the array.

Here is a simple program that prints out the first n numbers in the Fibonacci series in C:

Introduction to C

• First we should write the values in the memory.
• Move those values into the registers.(registers are also a kind of memory where the CPU can perform operation on the values stored in the registers.)
• Add the values in the registers.
• Save the result in the register to the memory.

• Array is collection of similar data items.
• An array can hold multiple values of same type of data
• In c programming language an array can be declared as datatype arrayName [ arraySize ]; 
• In c , while declaring an array we need to specify type of array , name of array and size of the array.
  
• One can directly initialize an array while declaring itself with some values
• int arrayVariable[2]=[10,20];
• int count[]=[1,2,3,4,5]
• directly initialize an array of particular : count[3]=10
• Let us discuss about how to initialize an array with some default values.
• Using for loop or while loop we can iterate an array and by accessing each index we can assign values 
• If we are not initializing an array and try to print all the values then it will print some garbage values.
• c initialize array of ints

#2 write a C Program to initialize an array values to 0 (zeros).

• In this  program we will discuss about how to check whether a character is vowel or consonant.
• In English language will be having 5 vowels and 21 consonants.
• To check entered character is vowel or consonant, first Read input character from user using scanf.
• There are only 5 vowels(A,E,I,O,U), so we need to check entered character is there in those 5 characters.
• If it is present then we can say its an vowel, otherwise it is a consonant.
• While checking we need to consider case sensitivity. So we need to check both uppercase vowels and lower case vowels.
• Lets see an example program to check whether entered character is vowel or not.

Write a program to determine whether the input character is a vowel or consonant or not an alphabet

• Lets discuss a program on how to print prime numbers from 1 to 100.
• Here by default we need to print all prime numbers from 1 to 100.
• No need to ask user to enter a number because we need to end loop at 100.
• Using for loop iterate from 1 to 100
• Take one more loop and check each number is divisible by 1 and itself or not.
• Program to print prime number between 1 to 100 in c

#1.C program to print prime numbers from 1 to 100

•  Check here for printing an integer in c 
• We have 4 basic data types in c programming language
• int, char, float and double
• For storing numbers or integers we will use int data type.
• Lets see an example program sum of two integers in c programming language.
• To add two integers we need two int type variables and third variable to store result of sum of two integers.
• Its a basic level example program for beginners to understand integer data types

• Please check this below program which prints even numbers from 1 to n.

• Print even numbers in c 
• To print sum of even numbers from 1 to n first we need to get all the even numbers and add them.
• Using for or while loop iterate from 1 to n number and get all even numbers
• sum=sum+evenNumber
• C program to find sum of even numbers using while loop

C program to find sum of even numbers using while loop

• Lets see how to write a c program to print even numbers using c programming.\
• Its a basic example to print only even numbers 
• Use for loop and iterate from 1 to n.
• In each iteration check if number if divisible by 2 (n%2 == 0). if yes then its a even number otherwise it is a odd number.
• C program to print even numbers from 1 to n. 

#2 print even numbers in c using while loop

• Now we will try to print even numbers using while loop
• Only difference is replace for with while loop
• Variable initialization will be done before loop
• condition will be inside while(condition)
• increment or decrement will be last line of while block 
• Lets print even numbers using while loop from 1 to n.

• To find sum of digits of a number in c , we need to get individual numbers and add those numbers.
• First of all read a number from user using scanf.
• Using while loop get individual number 
• Divide the number with 10 so we will get last digit of that number as remainder , once we get that last digit then add it to one variable and divide that number with 10 so it will become one digit less.
• like this we can get all digits and add all those numbers to get sum of digits 
• Sum of individual digits in c program
• c program to find sum of digits of a 3 digit number

correction: here n =number .

# program to find sum of digits of a number in c

1. #include<stdio.h> // include stdio.h
2. //c program to find sum of digits of a number using while loop
3. //write a program to find sum of digits of a number
4. //www.instanceofjava.com
5. int main()
6. {
7.     // declare variables 
8.     int number, remainder, sum = 0;
9.     //read input from user 
10.     printf("Enter a number: ");
11.     scanf("%d", &number);
12. 
    
13.    //iterate until number not equal to zero
14.    // get individual digits and add all those digits to get sum
15.     while(number != 0)
16.     {
17.         remainder = number % 10;
18.         sum += remainder;
19.         number = number / 10;
20.     }
21.   //print sum of digits in c
22.     printf("sum = %d", sum);
23. 
    
24.     getch();
25. }

• To check GCD of two numbers first we need to read input from user. i.e ask user to enter two numbers
• Store those two numbers in two integer variables
• Check if number is factor of given two numbers by iterating in for loop.

 c program to check whether the triangle is right angled triangle

• To check right angle triangle or not first we need to check sum of all three angles 
• If sum of all three angles is 180 then we it should satisfy second condition also
• Second condition is on of the angle should be 90.
• if both the conditions are passed then we can say it is a right angle triangle.
• Now lets write a c program to check triangle is right angle triangle or not.

• If reverse number of a number is same then we can say its a palindrome number
• we already know logic to reverse a number using remainder logic
• read input from the user and store it in a variable
• check reverse number of given number 
• compare original number and reverse number if both are same then we can say it's a palindrome number 
• C Program to Check Whether a Number is Palindrome or Not
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