If-Else Statements: The Decision Makers

In C programming, decision-making is crucial. Enter the if-else statements, your program's decision makers, guiding the flow of execution based on various conditions. They act like crossroads, where different paths lead to different outcomes based on the choices made.

If Statement: The Gatekeeper

The if statement is the gatekeeper, allowing your program to take a specific path if a certain condition is true. It checks the condition and, if true, lets the code inside its block run.

Syntax

Here’s the basic structure of an if statement:

if (condition) {
    // code to be executed if condition is true
}

Example

Let’s see the gatekeeper in action:

#include <stdio.h>

int main() {
    int number = 10;

    if (number > 5) {
        printf("The number is greater than 5.\n");
    }

    return 0;
}

In this example, the gatekeeper checks if number is greater than 5. If true, it prints a message.

Else Statement: The Backup Plan

What if the condition is false? The else statement steps in as the backup plan, providing an alternative path if the if condition isn't met.

Syntax

Adding an else gives your program a fallback:

if (condition) {
    // code to be executed if condition is true
} else {
    // code to be executed if condition is false
}

Example

Here’s an if-else in action:

#include <stdio.h>

int main() {
    int number = 3;

    if (number > 5) {
        printf("The number is greater than 5.\n");
    } else {
        printf("The number is 5 or less.\n");
    }

    return 0;
}

In this scenario, since number is 3, the else block executes, providing a different message.

Else If Statement: The Multi-Option Checker

Sometimes, decisions aren't binary. The else if statement lets you handle multiple conditions, checking each one in sequence until a match is found.

Syntax

Here’s how you use else if:

if (condition1) {
    // code to be executed if condition1 is true
} else if (condition2) {
    // code to be executed if condition2 is true
} else {
    // code to be executed if both conditions are false
}

Example

Let’s explore a more complex decision-making process:

#include <stdio.h>

int main() {
    int number = 10;

    if (number > 10) {
        printf("The number is greater than 10.\n");
    } else if (number == 10) {
        printf("The number is exactly 10.\n");
    } else {
        printf("The number is less than 10.\n");
    }

    return 0;
}

In this example, the program has three possible paths, checking if number is greater than, equal to, or less than 10.

Key Points

• If: The gatekeeper checks a condition and runs the code block if true.
• Else: The backup plan provides an alternative if the if condition is false.
• Else If: The multi-option checker allows handling multiple conditions, making your code more versatile.

When to Use If-Else Statements?

• If: Use when you need to execute code only if a specific condition is true.
• Else: Use when you need a fallback plan for when the if condition is false.
• Else If: Use when you have multiple conditions to check and need to choose among various paths.

Practice Exercise

Create a program that asks the user for a number and uses if-else statements to print whether the number is positive, negative, or zero.

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With if-else statements, you can make your programs smarter and more responsive to different scenarios. Next, explore the Switch Statement chapter to see another way of handling multiple conditions with style and ease.