If Statement:
- The statement will be executed only if the predefined condition is true.
Format:
If (condition) {
Statement
}
#include <iostream>
using namespace std;
int main(){ //Condition does not require semicolon.
int x = 10;
if (x<=10){
cout<<x; //Output will be 10 as in condition is evaluated as true
}
}
else Statement:
- Here if the predefined condition is true, then the statement will be executed, else it will execute another statement.
Format:
If (condition) { ----------------> Test the given condition
Statement -------------------> If the condition is found to be true, then this will executed
}
else {
statement --------------------> If condition is evaluated as false, then this will be executed
}
Example:
#include <iostream>
using namespace std;
int main(){
int age;
cout<<"Enter Your age"<<endl; //User will enter his/her age
cin>>age; // User's age will be stored in variable age
if (age<18){ // If age is less than 18
cout<<"You are not eligible for vote"<<endl; // Output executed: if the above condition is true
}
else { //Otherwise
cout<<"You are eligible for vote"<<endl; //Output executed: If the above condition is false
}
}
Nested If statements:
When we use multiple if statement within a program we structured them by using nesting format.
#include <iostream>
using namespace std;
int main(){
int age;
cout<<"BUS FARE CALCULATOR"<<endl;
cout<<"Enter Your age"<<endl; //User will enter his/her age
cin>>age; // User's age will be stored in variable age
if (age<=60){ // If age is less than 18
cout<<"Fare Calculated: 30 INR "<<endl; // Output executed: if the above condition is true
if (age<=5){
cout<<"No Fare Required"<<endl; // Output executed: if the above condition is true
}
} else {
if (age>=75) { // Otherwise if passenger's age is greater than equal to 75.
cout<<"Reserved Seat will be provided. Fare calculated: 5 INR"<<endl; // Output executed: if the above condition is true
} else { //Otherwise Fare for Passengers of age group 60-75
cout<<"Fare for senior citizen: 10 INR"<<endl;
}
}
}