 # C Programming Code Examples

## C > For Loops and While Loops Code Examples

### Program to find sum of first and last digit without using loop

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/* Program to find sum of first and last digit without using loop Write a C program to input a number and find sum of first and last digit of the number using for loop. How to find sum of first and last digit of a number in C programming using loop. Logic to find sum of first and last digit of a number without using loop in C program. C program to find sum of first and last digit of a number */ #include <stdio.h> #include <math.h> int main() { int j, sum, digits, firstDigit, lastDigit; sum = 0; /* Input a number from user */ printf("Enter any number to find sum of first and last digit: "); scanf("%d", &j); /* Find last digit */ lastDigit = j % 10; /* Find total number of digits - 1 */ digits = (int) log10(j); /* Find first digit */ firstDigit = (int) (j / pow(10, digits)); /* Calculate the sum */ sum = firstDigit + lastDigit; printf("Sum of first and last digit = %d", sum); return 0; }

The for loop is used in the case where we need to execute some part of the code until the given condition is satisfied. The for loop is also called as a per-tested loop. It is better to use for loop if the number of iteration is known in advance. The for-loop statement is a very specialized while loop, which increases the readability of a program. It is frequently used to traverse the data structures like the array and linked list.

Raise to power. Returns base raised to the power exponent: baseexponent. The function pow() is used to calculate the power raised to the base value. It takes two arguments. It returns the power raised to the base value. It is declared in "math.h" header file.

Relational Operators are the operators used to create a relationship and compare the values of two operands. For example, there are two numbers, 5 and 15, and we can get the greatest number using the greater than operator (>) that returns 15 as the greatest or larger number to the 5. Following are the various types of relational operators in C. Equal To Operator (==) is used to compare both operands and returns 1 if both are equal or the same, and 0 represents the operands that are not equal. Not Equal To Operator (!=) is the opposite of the Equal To Operator and is represented as the (!=) operator. The Not Equal To Operator compares two operands and returns 1 if both operands are not the same; otherwise, it returns 0.

Writes the C string pointed by format to the standard output (stdout). If format includes format specifiers (subsequences beginning with %), the additional arguments following format are formatted and inserted in the resulting string replacing their respective specifiers. printf format string refers to a control parameter used by a class of functions in the input/output libraries of C programming language. The string is written in a simple template language: characters are usually copied literally into the function's output, but format specifiers, which start with a % character, indicate the location and method to translate a piece of data (such as a number) to characters. "printf" is the name of one of the main C output functions, and stands for "print formatted". printf format strings are complementary to scanf format strings, which provide formatted input (parsing). In both cases these provide simple functionality and fixed format compared to more sophisticated and flexible template engines or parsers,

Read formatted data from stdin. Reads data from stdin and stores them according to the parameter format into the locations pointed by the additional arguments. The additional arguments should point to already allocated objects of the type specified by their corresponding format specifier within the format string. In C programming, scanf() is one of the commonly used function to take input from the user. The scanf() function reads formatted input from the standard input such as keyboards. The scanf() function enables the programmer to accept formatted inputs to the application or production code. Moreover, by using this function, the users can provide dynamic input values to the application.

#include is a way of including a standard or user-defined file in the program and is mostly written at the beginning of any C/C++ program. This directive is read by the preprocessor and orders it to insert the content of a user-defined or system header file into the following program. These files are mainly imported from an outside source into the current program. The process of importing such files that might be system-defined or user-defined is known as File Inclusion. This type of preprocessor directive tells the compiler to include a file in the source code program. Here are the two types of file that can be included using #include:

In C, the "main" function is treated the same as every function, it has a return type (and in some cases accepts inputs via parameters). The only difference is that the main function is "called" by the operating system when the user runs the program. Thus the main function is always the first code executed when a program starts. main() function is a user defined, body of the function is defined by the programmer or we can say main() is programmer/user implemented function, whose prototype is predefined in the compiler. Hence we can say that main() in c programming is user defined as well as predefined because it's prototype is predefined. main() is a system (compiler) declared function whose defined by the user, which is invoked automatically by the operating system when program is being executed.

Compute common logarithm. Returns the common (base-10) logarithm of x. Calculates the base-10 logarithm of a number. The log10() functions calculate the common logarithm of their argument. The common logarithm is the logarithm to base 10. The common logarithm of a number x is defined only for positive values of x. If x is negative, a domain error occurs; if x is zero, a range error may occur. Function returns common logarithm of x. If x is negative, it causes a domain error. If x is zero, it may cause a pole error (depending on the library implementation).

Load some random values into the linked list. Adds a node at the end of a linked list. If the list is empty, create first node. Go to last node. Add node at the end. Assign data to...

C Language program to calculates the area of trapezium. The Formula used in this program are Area = (1/2) * (x + y) * h where x and y are the Two Bases of Trapezium & h is the height.