by Dinesh Thakur Category: Control Structures

The Greatest Common Divisor of two positive integers can be calculated iteratively by the following formula known as Euclid's algorithm. You can see that this is a recursive definition with GCD(m,n) defined in terms of GCD(n,m%n).

 
by Dinesh Thakur Category: Control Structures

The if-else statement given below uses the leap year test to determine the number of days in February.

 
by Dinesh Thakur Category: Control Structures

The program segment given below obtains a number by reversing the digits in the given number.

 
by Dinesh Thakur Category: Control Structures

Consider that we wish to determine the result of a student in the SSC (Secondary School Certificate) examination, which has six subjects: four of 100 marks each and two of 150 marks each.

 
by Dinesh Thakur Category: Control Structures

In this example, we use two for loops in conjunction with the putchar library function to print all uppercase letters followed by all lowercase letters. The loop variable ch is assumed to be of type char or int. The first for loop prints the uppercase letters as loop variable ch assumes values as ‘A’, 'B’, ... , ‘z’.

 
by Dinesh Thakur Category: Control Structures

Perfect numbers are positive integers which have the special property that the sum of all their factors equals the number itself, e.g., 6 = 1+2+3. The C program finds and prints out all perfect numbers less than 1000.

 
by Dinesh Thakur Category: Control Structures

The trapezoidal rule is the simplest method to approximate the definite integral of a function f(x) over the interval [a, b]. Given N equally space points (with a spacing of h) X0, X1, ..., XN such that X0 = a and XN = b, the integral of f(x) can be approximated as the sum

 
by Dinesh Thakur Category: Control Structures

Let us use variables a and b of type float to represent two operands, variable c of type float to represent the result and variable op of type char to represent the operator. In the program given below, an expression of the form a op b is first accepted from the keyboard and a switch statement is used to evaluate the result.

 
by Dinesh Thakur Category: Control Structures

The continue statement is another loop interruption statement provided in the C language. It interrupts only the current iteration of the loop as opposed to the break statement which interrupts the execution of the entire loop. The format of the continue statement is as follows:

 
by Dinesh Thakur Category: Control Structures

The while loop is particularly suitable when the number of iterations is not known or can not be determined in advanced. In this section, another loop that is useful in similar situations, the do ... while loop is discussed.

 
by Dinesh Thakur Category: Control Structures

Consider that we have to add the given numbers until the desired sum is obtained (i. e., as long as the sum is less than a specified value).

 
by Dinesh Thakur Category: Control Structures

The for loop is used for repetitive execution of a statement or a group of statements. It is a very powerful and flexible statement of the C language. It is generally used in situations where the number of iterations of the loop statement is known or can be determined in advance.

 
by Dinesh Thakur Category: Control Structures

The program segment given below reads a number from the keyboard (in variable num of type float) and prints its square root. However, as the sqrt function requires a non-negative argument, the program uses a do ..while loop to read the data until valid data is entered.

 
by Dinesh Thakur Category: Control Structures

large= a> b? a : b;

This example illustrates how a conditional expression can be used to assign one of two alternative values to a variable depending on the outcome of some condition. As the conditional expression operator has higher precedence than the assignment operator, the above assignment statement is equivalent to

 
by Dinesh Thakur Category: Control Structures

Often we wish to perform more than one operation when the condition in an if statement evaluates as true and/or false as shown in Fig. In such situations, we use block statements (also called compound statements) within the if statement.

 
by Dinesh Thakur Category: Control Structures

The C language provides three loops (for,while and do ...while).As contained statement in the body of the loop can be any valid C statement, we can obtain several nested-loop structures by replacing this statement with another loop statement. Thus, if we replace the statement in a for loop with another for loop, we will get a two-level nested for loop as

 
by Dinesh Thakur Category: Control Structures

The while expression may consist of a single expression (as it is generally done in most of the programs); however, we may also use compound conditions or expressions. Multiple expressions may be connected by a comma operator or by Boolean operators. If the expressions are simply connected by comma, it is the last expression that is evaluated. The expressions preceding the last are ignored. In the following while expression the first expression, i.e., j <4 is neglected.

 
by Dinesh Thakur Category: Control Structures

A character is a whitespace if it is one of the following characters: blank space (' '), newline ('\n'), horizontal tab ('\t'), carriage return ('\r'), form feed ('\f') or vertical tab ('\v'). The if statement given below tests whether the given character ch is equal to one of these characters using logical or (||) operator and prints an appropriate message.

 
by Dinesh Thakur Category: Control Structures

The program segment given below using a do ...while loop and then determines the average of the given numbers.

 
by Dinesh Thakur Category: Control Structures

if (marks >= 0 && marks <= 100)

    printf("Valid marks");

    else printf("Invalid marks");

 

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About Dinesh Thakur

Dinesh ThakurDinesh Thakur holds an B.SC (Computer Science), MCSE, MCDBA, CCNA, CCNP, A+, SCJP certifications. Dinesh authors the hugely popular blog. Where he writes how-to guides around Computer fundamental , computer software, Computer programming, and web apps. For any type of query or something that you think is missing, please feel free to Contact us.



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