by Dinesh Thakur Category: Control Structures

The program segment given below accepts numbers from the keyboard until we enter a zero or a negative number and calculates their sum excluding the last number.

 
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 while loop is particularly useful when the number of iterations is not known or cannot be determined in advance. The general syntax of the while loop is as follows:

 
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

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

This code segment first accepts a range of values in variables m and n, both of type int. The variable num, also of type int, is used as the loop variable. It assumes values from m to n. For each value of loop variable num, the printf statement within the for loop is executed.

 
by Dinesh Thakur Category: Control Structures

The for loop given above prints a line of fifty dashes followed by a newline. The for loop uses i as the loop variable whose initial and final values are 0 and 49, respectively (note the < operator in i < 50). The update expression increments the value of i by 1.

 
by Dinesh Thakur Category: Control Structures

These statements determine and print the absolute value of variable n. If n is negative, then n < 0 evaluates as true and n is assigned the value of -n, which is then printed in the next statement assuming variable n to be of some integer type. However, if the value of n is positive, it remains unchanged and is printed.

 
by Dinesh Thakur Category: Control Structures

While performing a division operation, if the divisor is zero, the division by zero error occurs and program execution halts abruptly. The program segment given below calculates and prints the value of a/b without causing a division by zero error.

 
by Dinesh Thakur Category: Control Structures

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

    printf("Valid marks");

    else printf("Invalid marks");

 
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

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 accepts a character from the keyboard and prints the name of the corresponding color, e. g., if the user enters character R, it prints Red. However, it handles only three colors, namely, red, green and blue.

 
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

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

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

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 switch statement allows us to test an expression and depending on its value, execute a statement (or group of statements) amongst several alternatives. It is the most involved statement provided in C language. It uses four keywords, namely, switch, case, default and break. The last two keywords are optional and can be omitted. The general form of this statement is given below and its flowchart is shown in.

 
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

1. Factorial of a number.
2. Prime or not
3. Odd or even
4. Exit

Once a menu item is selected the appropriate action should be taken and once this action is finished, the menu should reappear. Unless the user selects the 'Exit' option the program should continue to work. 

 

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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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