➤ If-else Statement in C
➤ Programs on if-else
➤ Switch Case in C
➤ Switch case Programs
➤ Conditional Operator
➤ While loop in C
➤ Do-while loop in C
➤ While vs do-while
➤ For loop in C
➤ Break keyword in C
➤ Continue keyword in C
➤ Break vs Exit in C
➤ Goto keyword in C
☕️ Flow Control Programs
➤ Largest in 3 Numbers
➤ Find Grade of student
➤ Find the absolute value
➤ Vowel or Consonant
➤ Leap Year Program
➤ Simple calculator in C
➤ Check Odd or Even
➤ Roots of Quadratic Equation
➤ Find Reverse of Number
➤ Factors of a number in C
➤ Generate Multiplication table
➤ Find Power of a Number
➤ Find GCD and LCM
➤ Find factorial of Number
➤ Count Number of Digits
➤ Sum of digits in Number
➤ Sum of N Natural Numbers
➤ Sum of Squares of Natural No.
➤ Find Sum of Odd Numbers
➤ Find the Sum of Series
➤ Find Fibonacci series in C
➤ Sum of the Fibonacci series
➤ Sum until enters +ve numbers
➤ Sum of max 10 no. & Skip -ve
☕️ C Conversion Programs
➤ Celsius to Fahrenheit
➤ Fahrenheit to Celsius
➤ Decimal ↔ Binary
➤ Decimal ↔ Octal
➤ Octal ↔ Binary in C
☕️ Number Programs in C
➤ Prime Number in C
➤ Strong Number in C
➤ Krishnamurthy Number
➤ Neon Number in C
➤ Palindrome number
➤ Perfect Number in C
➤ Armstrong Number
☕️ Pattern Programs in C
➤ Pattern programs in C
➤ Printing pattern using loops
➤ Floyd’s triangle Program
➤ Pascal Triangle Program
➤ Pyramid Star Pattern in C
➤ Diamond Pattern Programs
➤ Half Diamond pattern in C
➤ Print Diamond Pattern
➤ Hollow Diamond Pattern
➤ Diamond Pattern of Numbers
In mathematics, the factorial of a positive integer n, denoted by n! It is the product of all positive integers less than or equal to n. For example:- The factorial of 4= 4! = 4*3*2*1 or 1*2*3*4 = 24 Here we will write the Factorial program in C programming language.
Factorial (n) = 1 * 2 * …. * (n-1) * n
Or,
Factorial (n) = n * (n-1) * ….. * 2 * 1
The factorial of a negative number doesn’t exist. The value of 0! is 1, according to the convention for an empty product.
Factorial of a Number in C using For loop
The for loop in C programming language is a pre-test loop, where first of all initialization expression is evaluated then the condition is checked and if the condition is true then only the statements of the for loop are executed.
The for loop contains the initialization, update, and test_condition in one statement, so it makes for very readable code. All the control steps, initialization, end-of-loop test, and updating are done in one place.
We can use the increment operator to find the factorial of a number. So, using increment operator the 4! is evaluated as 1*2*3*4
Factorial program using for loop and increment (++) operator
#include<stdio.h>
int main()
{
int number, i, fact=1;
printf("Enter number: ");
scanf("%d", &number);
for(i=1; i<=number; i++)
{
fact *= i; // fact = fact * i
}
printf("%d! = %d", number, fact);
return 0;
}
Output:-
Enter number: 5
5! = 120
Factorial of a Number Using for loop and decrement (--)
operator
We can use the decrement operator to find the factorial of a number. So, using the decrement operator for 4! = 4*3*2*1
#include<stdio.h>
int main()
{
int number, i, fact=1;
printf("Enter number:");
scanf("%d",&number);
for(i=number; i>0; i--)
{
fact *= i; // fact = fact * i
}
printf("%d! = %d", number, fact);
return 0;
}
In this case, initialize the variable i
with the number and use decrement operation as update expression until the number is greater than zero.
Factorial program in C using while loop
We can also write the factorial program in C using while loop. While loop in C is a pre-test loop where the expression is evaluated then only statements are executed. It uses a test expression to control the loop. Before every iteration of the loop, the test expression is evaluated.
#include<stdio.h>
int main()
{
int number, i=1, fact=1;
printf("Enter number:");
scanf("%d",&number);
while(i<=number)
{
fact *= i;
i++;
}
printf("%d! = %d", number, fact);
return 0;
}
Using the do-while loop
The do-while loop in C is very closely related to the while loop. The do keyword is placed on a line of code at the top of the loop. A block of statements follows it with a test expression after the keyword while, at the bottom of the loop.
It is a post-test loop. The post-test loop executes at least, only then control expression is tested. If the expression is true, the loop repeats. When the expression is false then the loop terminates.
We can also use the do-while loop to write the factorial program in C.
#include<stdio.h>
int main()
{
int number, i=1, fact=1;
printf("Enter number: ");
scanf("%d",&number);
do
{
fact *= i;
i++;
} while(i<=number);
printf("%d! = %d", number, fact);
return 0;
}
See also:- Factorial program in C using a function, Factorial program in C using Recursion
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Very Nice Blog.