In C, the if...else statement is used to make decisions in your code — to run different blocks of code depending on whether a condition is true or false. ??

? Basic Syntax

c
#include <stdio.h>int main() {    int num = 10;    if (num > 0) {        printf("Positive number\n");    } else {        printf("Zero or negative number\n");    }    return 0;}

Output:

typescript
Positive number

? if...else if...else

You can chain multiple conditions:

c
int age = 18;if (age < 13) {    printf("Child\n");} else if (age < 20) {    printf("Teen\n");} else {    printf("Adult\n");}

? Real-World Example

c
int marks = 85;if (marks >= 90) {    printf("Grade: A\n");} else if (marks >= 80) {    printf("Grade: B\n");} else if (marks >= 70) {    printf("Grade: C\n");} else {    printf("Grade: F\n");}

?? Notes

• The condition inside if must return true (non-zero) or false (zero)

• Use comparison operators like ==, !=, <, >, <=, >=

• Use logical operators like &&, ||, ! for complex conditions

Want to explore nested if, ternary operator (? :), or compare with switch? I’ve got you covered!