Conditional Statements

In C, conditional statements allow a program to make decisions based on certain conditions.

In this lesson, you will learn how to use if, else, and switch statements to control program flow.

The if statement executes a block of code only if a condition is true.

Syntax:

if (condition) { // Code to execute if condition is true }

This program checks if a number is positive.

#include <stdio.h>

int main() {
    int num = 10;
    if (num > 0) {
        printf("The number is positive.\n");
    }
    return 0;
}

The if-else statement executes one block of code if the condition is true and another block if the condition is false.

Syntax:

if (condition) { // Code if condition is true } else { // Code if condition is false }

This program checks if a number is positive or negative.

#include <stdio.h>

int main() {
    int num = -5;
    if (num > 0) {
        printf("Positive number.\n");
    } else {
        printf("Negative number.\n");
    }
    return 0;
}

You can use multiple if statements inside one another.

Example:

if (condition1) { if (condition2) { // Code block } }

The switch statement is an alternative to multiple if-else conditions.

Syntax:

switch (variable) { case value1: // Code block break; case value2: // Code block break; default: // Default block }

This program prints the name of a day based on an integer input.

#include <stdio.h>

int main() {
    int day = 3;
    switch (day) {
        case 1:
            printf("Monday\n");
            break;
        case 2:
            printf("Tuesday\n");
            break;
        case 3:
            printf("Wednesday\n");
            break;
        default:
            printf("Invalid day\n");
    }
    return 0;
}

In this lesson, you learned:

• How to use if, if-else, and switch statements.
• How to use nested if statements for complex conditions.
• The difference between if-else and switch.

Next, we will explore looping structures in C!