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

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

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

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: 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 outer for loop is set up to process each number in the given range. Each number is tested within this loop using the simplified code. The execution of the break statement causes inner for loop to terminate as it is the nearest loop enclosing the break statement. If the inner for loop is completely executed, i. e., if condition d == num is true, num is printed as a prime number.

 
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

Consider that we wish to print a given positive integer number in words, as a sequence of digit strings. For example, number 123 should be printed as One Two Three. This might be required in financial applications, for example, to print the cheque amount in words.

 
by Dinesh Thakur Category: Control Structures

Three positive integer numbers a, band c, such that a<b<c form a Pythagorean triplet if c2= a2 +b2 , i. e,, a, b and c form the sides of a right-angled triangle. To select the values of a and b such that a < b and a, b < max, we can use nested for loops as shown below:

 
by Dinesh Thakur Category: Control Structures

As the name indicates, the prime factors of a given number are its factors that are also prime numbers, e.g., prime factors of 30 are 2, 3 and 5 but not 1, 6, 10, 15 and 30. One or more prime factors of a given number may repeat, e. g., prime factors of 120 are 2, 2, 2, 3 and 5.

 
by Dinesh Thakur Category: Control Structures

The program segment given below determines the sum of digits of a given number repeatedly until a single digit number is obtained. For example, 5985 => 27 => 9, where symbol => indicates a digit sum operation. Thus, if digit sum exceeds 9, it is used as a number for subsequent digit sum operations.

 
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 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

This program segment given below uses a straight-forward approach to count the number of odd and even digits in a given integer number(num).

 
by Dinesh Thakur Category: Control Structures

The program segment given below prints four-digit special perfect square numbers in which the upper and lower two-digit numbers are perfect squares as well.

 
by Dinesh Thakur Category: Control Structures

Let us use variables dd,mm and yy (all of type int)to represent the day, month and year in a given date. The given date is valid only if year (yy)is non-zero, month (mm)is in the range 1 to 12 and day of month (dd) is in the range 1 to mdays, the number of days in a given month mm. An algorithm to determine the validity of a given date is given below.

 
by Dinesh Thakur Category: Control Structures

In this example, a for loop is set up with values of loop variable num from m to n. The if statement is executed for each value of num and if nums an odd number (num%2 equals 1), it is printed using the printf statement. The output of this code is given below for m= 20 and n=40.

 
by Dinesh Thakur Category: Control Structures

The if statement within the body of the for loop is used to print a comma after each value of the loop variable except the last one.

Consider the code given below to print a comma-separated list of numbers from 1 to 10:

 
by Dinesh Thakur Category: Control Structures

Both the switch and if-else-if statements enable us to select one of several alternative statements for execution. However, they differ in several aspects:

 

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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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