If Else in C

if-else is used when a program has to choose between two or more paths. The condition is checked first. If it is true, the if block runs; otherwise the else block runs.

Syntax / Basic Pattern

if (condition) {
// true block
} else {
// false block
}

Easy points to remember

Use if-else for decisions such as pass/fail, even/odd, eligibility and comparisons.
For more than two choices, use else-if.
Use == for comparison; use = for assignment.

⭐ PRACTICE TIP: Type these programs yourself. Change the values and run them again. That is how control statements become easy.

Program 1: Positive or negative

#include <stdio.h>
int main(){ int n=12; if(n>=0) printf(“Non-negative”); else printf(“Negative”); return 0;}

OUTPUT
Non-negative

Program 2: Even or odd

#include <stdio.h>
int main(){ int n=17; if(n%2==0) printf(“Even”); else printf(“Odd”); return 0;}

OUTPUT
Odd

Program 3: Pass or fail

#include <stdio.h>
int main(){ int marks=68; if(marks>=40) printf(“Pass”); else printf(“Fail”); return 0;}

OUTPUT
Pass

Program 4: Adult or minor

#include <stdio.h>
int main(){ int age=17; if(age>=18) printf(“Adult”); else printf(“Minor”); return 0;}

OUTPUT
Minor

Program 5: Greater of two

#include <stdio.h>
int main(){ int a=25,b=19; if(a>b) printf(“%d is greater”,a); else printf(“%d is greater”,b); return 0;}

OUTPUT
25 is greater

Program 6: Divisible by 5

#include <stdio.h>
int main(){ int n=45; if(n%5==0) printf(“Divisible by 5”); else printf(“Not divisible by 5”); return 0;}

OUTPUT
Divisible by 5

Program 7: Profit or loss

#include <stdio.h>
int main(){ float cp=500,sp=620; if(sp>cp) printf(“Profit = %.2f”,sp-cp); else printf(“No profit”,0.0); return 0;}

OUTPUT
Profit = 120.00

Program 8: Eligible to vote

#include <stdio.h>
int main(){ int age=22; if(age>=18) printf(“Eligible to vote”); else printf(“Not eligible”); return 0;}

OUTPUT
Eligible to vote

Program 9: Largest of three

#include <stdio.h>
int main(){ int a=15,b=42,c=28; if(a>=b&&a>=c) printf(“Largest=%d”,a); else if(b>=a&&b>=c) printf(“Largest=%d”,b); else printf(“Largest=%d”,c); return 0;}

OUTPUT
Largest=42

Program 10: Grade

#include <stdio.h>
int main(){ int m=76; if(m>=90) printf(“A+”); else if(m>=75) printf(“A”); else if(m>=60) printf(“B”); else if(m>=40) printf(“C”); else printf(“F”); return 0;}

OUTPUT
A

Program 11: Leap year

#include <stdio.h>
int main(){ int y=2024; if((y%400==0)||(y%4==0&&y%100!=0)) printf(“Leap year”); else printf(“Not leap year”); return 0;}

OUTPUT
Leap year

Program 12: Number in range

#include <stdio.h>
int main(){ int n=35; if(n>=1&&n<=50) printf(“Inside range”); else printf(“Outside range”); return 0;}

OUTPUT
Inside range

Program 13: Character vowel

#include <stdio.h>
int main(){ char ch=’e’; if(ch==’a’||ch==’e’||ch==’i’||ch==’o’||ch==’u’) printf(“Vowel”); else printf(“Consonant”); return 0;}

OUTPUT
Vowel

Program 14: Temperature check

#include <stdio.h>
int main(){ float t=38.5; if(t>=40) printf(“Very hot”); else if(t>=30) printf(“Hot”); else printf(“Moderate”); return 0;}

OUTPUT
Hot

Program 15: Login check

#include <stdio.h>
#include <string.h>
int main(){ char user[]=”admin”, pass[]=”1234″; if(strcmp(user,”admin”)==0&&strcmp(pass,”1234″)==0) printf(“Login successful”); else printf(“Invalid login”); return 0;}

OUTPUT
Login successful