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Conditionals in C

What are Conditionals?​

Conditionals in C allow you to execute different parts of your code based on certain conditions. They help control the flow of the program by making decisions.

Types of Conditional Statements​

1. if Statement​

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

Syntax:​

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

Example:​

int num = 10;
if (num > 0) {
    printf("Number is positive.\n");
}

2. if-else Statement​

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

Example:​

int num = -5;
if (num > 0) {
    printf("Number is positive.\n");
} else {
    printf("Number is non-positive.\n");
}

3. else if Statement​

You can chain multiple conditions using else if to check multiple conditions in sequence.

Syntax:​

if (condition1) {
    // code for condition1
} else if (condition2) {
    // code for condition2
} else {
    // code if none of the above conditions are true
}

Example:​

int num = 0;
if (num > 0) {
    printf("Number is positive.\n");
} else if (num < 0) {
    printf("Number is negative.\n");
} else {
    printf("Number is zero.\n");
}

4. switch Statement​

The switch statement is used to select one of many blocks of code to be executed. It is often used as a more readable alternative to a series of if-else statements.

Syntax:​

switch (expression) {
    case constant1:
        // code to be executed if expression equals constant1
        break;
    case constant2:
        // code to be executed if expression equals constant2
        break;
    default:
        // code to be executed if expression doesn't match any constant
}

Example:​

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("Not a valid day\n");
}

Conditional Operators​

C also provides several operators that can be used to form conditions.

1. Relational Operators​

  • == : Equal to
  • != : Not equal to

  • : Greater than

  • < : Less than

  • = : Greater than or equal to

  • <= : Less than or equal to

2. Logical Operators​

  • && : Logical AND
  • || : Logical OR
  • ! : Logical NOT

Example:​

int a = 5, b = 10;
if (a < b && a > 0) {
    printf("a is positive and less than b.\n");
}

Summary

  • Conditionals allow you to control the flow of your program based on certain conditions.
  • The primary conditional statements are if, if-else, else if, and switch.
  • Relational and logical operators are used to create complex conditions.