if else in C

4 Key excerpts on "if else in C"

• 

  eBook - ePub

  'C' Programming in an Open Source Paradigm

  • K. S. Oza, S. R. Patil, R. K. Kamat(Authors)
  • 2022(Publication Date)
  • River Publishers

    (Publisher)

  C language has three branching statements: if statement, if-else statement, and switch statement. These statements control the behavior of a program. Each branch consists of set of instructions to be executed depending upon some condition. If that condition evaluates to true, then the corresponding block of statements get executed. The “if statement” is the simplest form. It takes an expression in parenthesis, and if the expression evaluates to true, then the statement/statements get executed; otherwise, they are skipped.

  2.2 The if Statement

  The if statement is used to make one time decision. Here either the statement is true or false, like binary decision. General form:

  if (condition is true)

      execute statement;

  where if is a keyword:    condition—expression using C’s relational operator    statement—block of code to be executed. The block of code is executed if and only if the condition is true; otherwise, compiler skips it.

  2.3 The if-else Statement

  The if statement facilitates execution of block of code if condition is true; otherwise, it does nothing. The if-else statement provides a way to execute a set of instructions if condition is true or false.

  General form:

  if (condition is true)

         execute statement;

  else

         execute statement;  // if condition is false

  Here, else part will execute if condition will evaluate to false.

  Program 2.1 Use of if-else statement to predict leap year Leap year comes once in four years. It has 29 days in February. User is asked to enter the year, which is then divided by 4; and if the remainder is zero, then the year is leap year, else not.

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  eBook - ePub

  ANSI C Programming

  Learn ANSI C step by step

  • Yashavant Kanetkar(Author)
  • 2020(Publication Date)
  • BPB Publications

    (Publisher)

  4 The Decision Control Structure Decisions! Decisions! The if Statement The Real Thing Multiple Statements within if The if-else Statement Nested if-elses Forms of if Use of Logical Operators The else if Clause The ! Operator Hierarchy of Operators Revisited A Word of Caution The Conditional Operators Summary Exercise W e all need to alter our actions in the face of changing circumstances. If the weather is fine, then I will go for a stroll. If the highway is busy, I would take a diversion. If the pitch takes spin, we would win the match. If she says no, I would look elsewhere. If you like this book, I would write the next edition. You can notice that all these decisions depend on some condition being met. C language too must be able to perform different sets of actions depending on the circumstances. In fact, this is what makes it worth its salt. C has three major decision making instructions—the if statement, the if-else statement, and the switch statement. A fourth, somewhat less important structure is the one that uses conditional operators. In this chapter, we will explore all these ways (except switch, which has a separate chapter devoted to it, later) in which a C program can react to changing circumstances. Decisions! Decisions! In the programs written in Chapter 1, we have used sequence control structure in which the various steps are executed sequentially, i.e. in the same order in which they appear in the program. In fact, to execute the instructions sequentially, we don’t have to do anything at all. By default, the instructions in a program are executed sequentially. However, in serious programming situations, seldom do we want the instructions to be executed sequentially. Many a time, we want a set of instructions to be executed in one situation, and an entirely different set of instructions to be executed in another situation. This kind of situation is dealt with in C programs using a decision control instruction

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  eBook - PDF

  Programming with C++

  • Kyla McMullen, Elizabeth Matthews, June Jamrich Parsons, , Kyla McMullen, Kyla McMullen, Elizabeth Matthews, June Jamrich Parsons(Authors)
  • 2021(Publication Date)
  • Cengage Learning EMEA

    (Publisher)

  All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. PROGRAMMING WITH C++ 96 To handle algorithms that require multiple conditions, you can use an else-if structure. Figure 6-14 provides the syntax, rules, and best practices. Syntax: if (condition) statement; else if (condition) statement; else if (condition) { statement; statement; } else statement; Rules and best practices: • Begin with an if statement. • Use the keyword else if for subsequent conditional statements. • When else-if blocks contain more than one statement, use curly braces. • Use the keyword else for the final condition. • No semicolon is necessary after the parentheses or else keyword. Figure 6-14 Syntax for an else-if structure Figure 6-15 contains code for a program that uses an else-if structure to handle menu selections. Else If Structures (6.3.5) Programming languages provide syntax for structures that involve multiple conditions. Suppose you want to offer customers a menu of the following options: Press or say 1 to connect to an account agent. Press or say 2 to troubleshoot your cable service. Press or say 3 to troubleshoot your Internet connection. Press or say 0 to quit. Copyright 2022 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

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  eBook - PDF

  Java Programming

  • Joyce Farrell(Author)
  • 2018(Publication Date)
  • Cengage Learning EMEA

    (Publisher)

  He developed a type of linguistic algebra, based on 0s and 1s, the three most basic operations of which were (and still are) AND, OR, and NOT. Programming logic is based on his discoveries. Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 233 The if and if…else Statements In Java, when you want to take an action if a Boolean expression is true, you use an if statement. If you want to take an action when a Boolean expression is true but take a different action when the expression is false, you use an if…else statement. The if Statement The simplest statement you can use to make a decision is the if statement. An if statement is sometimes called a single-alternative selection because there is only one alternative—the true alternative. For example, suppose you have declared an integer variable named quizScore, and you want to display a message when the value of quizScore is 10. The if statement in Figure 5-3 makes the decision whether to produce output. Note that the double equal sign ( 55 ) is used to determine equality; it is Java’s equivalency operator. The false statement is #1. Pseudocode and flowcharts are both tools that help programmers plan a program’s logic. TWO TRUTHS & A LIE Planning Decision-Making Logic 1. Pseudocode and flowcharts are both tools that are used to check the syntax of computer programs. 2. In a sequence structure, one step follows another unconditionally. 3. In a decision structure, alternative courses of action are chosen based on a Boolean value.

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