If, If-else, else-if

if statement:

An if statement in C is a control structure used to perform conditional execution of code. It allows the program to execute a block of code only if a specified condition evaluates to true. If the condition is false, the code inside the if block is skipped.

if (condition) {

// Code to execute if condition is true

}

• Example: Checking if a Number is Positive

#include <stdio.h>int main() {
int number;

// Prompt user for input
printf(“Enter a number: “);
scanf(“%d”, &number);

// If statement to check if the number is positive
if (number > 0) {
printf(“The number is positive.\n”);
}

return 0;
}

• output

Enter a number: 10

The number is positive.

• output

Enter a number: -10

NOTE: NOTHING TO PRINT

 

if-else statement:

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

Example: Checking if a Number is Positive or Negative

#include <stdio.h>

int main() {
int number;

// Prompt user for input
printf(“Enter a number: “);
scanf(“%d”, &number);

// If statement to check if the number is positive or negative
if (number > 0) {
printf(“The number is positive.\n”);
}

else {
printf(“The number is negative.\n”);
}

return 0;
}

• output

Enter a number: 10

The number is positive.

• output

Enter a number: -10

The number is negative.

else if

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