23. User defined function develop a program to create a function to find the GCD of a given number call this function in c program

#include <stdio.h> 
#include <conio.h> 
int main() 
{ 
    // declare the variables 
    int n1, n2, i, GCD_Num; 
    printf ( " Enter any two numbers: \n "); 
    scanf ( "%d %d", &n1, &n2);  
     
    // use for loop 
    for( i = 1; i <= n1 && i <= n2; ++i) 
    { 
        if (n1 % i ==0 && n2 % i == 0) 
            GCD_Num = i;  /* if n1 and n2 is completely divisible by i, the divisible number will be the GCD_Num */   

    } 

    // print the GCD of two numbers 
    printf (" GCD of two numbers %d and %d is %d.", n1, n2, GCD_Num); 
    return 0; 
} 

Practical Lists with Source Code :

1. Develop minimum 2 program using constants variables, arithmetic expression.
2. Develop minimum 2 programs increment/decrement operators, exhibiting data type conversion.
3. Write a simple program to convert temperature in a Fahrenheit degrees to Centigrade degrees in c programming.
4. Write a simple program to calculate the area and the parameter of a rectangle and the area of circumference of the circle
5. Write a program to determine whether a given year is a leap year in c programming
6. Write a program to determine whether a string is palindrome in c programming
7. Write a program to find the greatest of the three number using conditional operators in C program
8. Write a program to find if a given character is vowel in C program
9. Using switch statement write a program to print a day of the week by taking a number from 1 to 7 in C programming
10. Using a switch statement write a program to print the students grade by accepting a percent marks in C programming 
11. Using switch statement write programs to check whether the triangle is isosceles, equilateral, scalene or right angled triangle.
12. Looping write a program to find the sum of a digit of a given number in C program
13. Looping write a program to generate multiplication table up to 10 for numbers 1 to 5 in C program
14. Write a program to find the Fibonacci series in the given number in C programming
15. Write a program to produce the following input1 2 3 4 5 6 7 8 9 10
16. Array develop a program to sort the list of the number 10 in c programming
17. Array write a program to perform the addition of 3 x3 matrix in C programming
18. Structure developer program to create a structure called library to hold details of a book viz, the book, and flag indicating whether book is issued or not fetch some sample data and display the same in c programming C programming.
19. Structure develop a program to execute C program to add two distance given in a kilometer using a structure in a C program.
20. Library function develop program to demonstrate use of all string handling function in c programing.
21. Library use of few mathematical function in C programming. 
22. Library functions develop program to demonstrate use of few other Miscellaneous C programs 
23. User defined function develop a program to create a function to find the GCD of a given number call this function in c program.