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");

 
by Dinesh Thakur Category: Control Structures

C program to sum the series 1/12+1/22+1/32

 
by Dinesh Thakur Category: Control Structures

In the expression for for loop the inclusion of the expressions are optional. However, two semicolons must be included. An endless for loop may be written as shown below.

 
by Dinesh Thakur Category: Control Structures

As a good programming practice, we display a message to prompt the user before accepting data from the keyboard. This enables the user to enter the required data correctly. However, the user may still enter incorrect data. Such data may cause the programs to print incorrect results.

 
by Dinesh Thakur Category: Control Structures

The program segment given below accepts an integer number in variable digit of type int from the keyboard and if it is a single digit number (0-9), it displays the word corresponding to it;

 
by Dinesh Thakur Category: Control Structures

The program segment given below accepts marks in a single subject and uses a nested if statement to determine the validity of marks and the result if the value of marks is valid. This code can be written in a more readable form using an if-else-if statement as

 
by Dinesh Thakur Category: Control Structures

We have seen that a break statement is usually used in a switch statement after the statements in each case. The execution of such a break statement causes the execution of the switch statement to be terminated and the control to be transferred to the statement following the switch statement.

 
by Dinesh Thakur Category: Control Structures

In this example, the initial value of loop variable j (of type int) is 100 and the update expression (j -= 10) reduces it by 10 after each iteration of the for loop.

 
by Dinesh Thakur Category: Control Structures

Nested for loops have many applications, particularly, in programs dealing with sorting of lists, input/output of multi-dimensional arrays, etc. and also in the evaluation of expressions involving more than one parameter. The code for nested/or loops is given below.

 
by Dinesh Thakur Category: Control Structures

So far, we have used only one variable in a for loop; however, more than one variable with different end values and with different modes of increments/decrements may also be used. In a compound for expression, the variables may be separated by a comma as illustrated for i and j below.

 
by Dinesh Thakur Category: Control Structures

There are several situations where more than one parameter need to be varied over a range of values to obtain the desired results. For example, there may be a function having two variables, say x and y and it is desired to evaluate the function for different values of x and y. In such cases, for every value of x the values of y are varied over the range of values of y. This calls for nested while expressions as illustrated below.

 
by Dinesh Thakur Category: Function and Pointer

Argument: An argument is an expression which is passed to a function by its caller (or macro by its invoker) in order for the function(or macro) to perform its task. It is an expression in the comma-separated list bound by the parentheses in a function call expression.

 
by Dinesh Thakur Category: Function and Pointer

We saw that pointer values may be assigned to pointers of same type. However, pointers may be type cast from one type to another type. In the following code lines, A is an int type variable, D is variable of type double, and ch is a variable of type char. Pa is declared as a pointer to int variables, Pd is declared as a pointer to double type variables, and Pc is declared as pointer to character type variables. Pa is assigned the value &A.

 
by Dinesh Thakur Category: Function and Pointer

Let us write a program to calculate the area' and circumference of a circle using user-defined functions. A function area_circum to accept the radius of a circle and print its area and circumference is given in Example. However, rather than printing the results in a function, it is good practice to return the results to the calling function, where they can be printed or used for further processing, if required. Hence, let us return the results (area and circumference) to the calling function.

 

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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.