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Statements in C++

C++ if-else

In C++ programming, if statement is used to test the condition. There are various types of if statements in C++.

  • if statement
  • if-else statement
  • nested if statement
  • if-else-if ladder

C++ IF Statement

The C++ if statement tests the condition. It is executed if condition is true.

  1. if(condition){    
  2. //code to be executed    
  3. }  
Cpp If else 1

C++ If Example

  1. #include <iostream>  
  2. using namespace std;  
  3.    
  4. int main () {  
  5.    int num = 10;    
  6.             if (num % 2 == 0)    
  7.             {    
  8.                 cout<<"It is even number";    
  9.             }   
  10.    return 0;  
  11. }  

Output:/p>

It is even number

C++ IF-else Statement

The C++ if-else statement also tests the condition. It executes if block if condition is true otherwise else block is executed.

  1. if(condition){    
  2. //code if condition is true    
  3. }else{    
  4. //code if condition is false    
  5. }    
Cpp If else 2

C++ If-else Example

  1. #include <iostream>  
  2. using namespace std;  
  3. int main () {  
  4.    int num = 11;    
  5.             if (num % 2 == 0)    
  6.             {    
  7.                 cout<<"It is even number";    
  8.             }   
  9.             else  
  10.             {    
  11.                 cout<<"It is odd number";    
  12.             }  
  13.    return 0;  
  14. }  

Output:

It is odd number

C++ If-else Example: with input from user

  1. #include <iostream>  
  2. using namespace std;  
  3. int main () {  
  4.     int num;  
  5.     cout<<"Enter a Number: ";  
  6.     cin>>num;  
  7.             if (num % 2 == 0)    
  8.             {    
  9.                 cout<<"It is even number"<<endl;    
  10.             }   
  11.             else  
  12.             {    
  13.                 cout<<"It is odd number"<<endl;    
  14.             }  
  15.    return 0;  
  16. }  

Output:

Enter a number:11
It is odd number

Output:

Enter a number:12
It is even number

C++ IF-else-if ladder Statement

The C++ if-else-if ladder statement executes one condition from multiple statements.

  1. if(condition1){    
  2. //code to be executed if condition1 is true    
  3. }else if(condition2){    
  4. //code to be executed if condition2 is true    
  5. }    
  6. else if(condition3){    
  7. //code to be executed if condition3 is true    
  8. }    
  9. ...    
  10. else{    
  11. //code to be executed if all the conditions are false    
  12. }    
Cpp If else 3

C++ If else-if Example

  1. #include <iostream>  
  2. using namespace std;  
  3. int main () {  
  4.        int num;  
  5.        cout<<"Enter a number to check grade:";    
  6.        cin>>num;  
  7.             if (num <0 || num >100)    
  8.             {    
  9.                 cout<<"wrong number";    
  10.             }    
  11.             else if(num >= 0 && num < 50){    
  12.                 cout<<"Fail";    
  13.             }    
  14.             else if (num >= 50 && num < 60)    
  15.             {    
  16.                 cout<<"D Grade";    
  17.             }    
  18.             else if (num >= 60 && num < 70)    
  19.             {    
  20.                 cout<<"C Grade";    
  21.             }    
  22.             else if (num >= 70 && num < 80)    
  23.             {    
  24.                 cout<<"B Grade";    
  25.             }    
  26.             else if (num >= 80 && num < 90)    
  27.             {    
  28.                 cout<<"A Grade";    
  29.             }    
  30.             else if (num >= 90 && num <= 100)    
  31.             {    
  32.                 cout<<"A+ Grade";  
  33.             }    
  34.     }    

Output:

Enter a number to check grade:66
C Grade

Output:

Enter a number to check grade:-2
wrong number

C++ switch

The C++ switch statement executes one statement from multiple conditions. It is like if-else-if ladder statement in C++.

  1. switch(expression){      
  2. case value1:      
  3.  //code to be executed;      
  4.  break;    
  5. case value2:      
  6.  //code to be executed;      
  7.  break;    
  8. ......      
  9.       
  10. default:       
  11.  //code to be executed if all cases are not matched;      
  12.  break;    
  13. }    
Cpp Switch 1

C++ Switch Example

  1. #include <iostream>  
  2. using namespace std;  
  3. int main () {  
  4.        int num;  
  5.        cout<<"Enter a number to check grade:";    
  6.        cin>>num;  
  7.            switch (num)    
  8.           {    
  9.               case 10: cout<<"It is 10"; break;    
  10.               case 20: cout<<"It is 20"; break;    
  11.               case 30: cout<<"It is 30"; break;    
  12.               default: cout<<"Not 10, 20 or 30"; break;    
  13.           }    
  14.     }    

Output:

Enter a number:
10
It is 10

Output:

Enter a number:
55
Not 10, 20 or 30

C++ For Loop

The C++ for loop is used to iterate a part of the program several times. If the number of iteration is fixed, it is recommended to use for loop than while or do-while loops.

The C++ for loop is same as C/C#. We can initialize variable, check condition and increment/decrement value.

  1. for(initialization; condition; incr/decr){    
  2. //code to be executed    
  3. }    

Flowchart:

Cpp For loop 1

C++ For Loop Example

  1. #include <iostream>  
  2. using namespace std;  
  3. int main() {  
  4.          for(int i=1;i<=10;i++){      
  5.             cout<<i <<"\n";      
  6.           }       
  7.     }   

Output:

1
2
3
4
5
6
7
8
9
10

In C++, we can use for loop inside another for loop, it is known as nested for loop. The inner loop is executed fully when outer loop is executed one time. So if outer loop and inner loop are executed 4 times, inner loop will be executed 4 times for each outer loop i.e. total 16 times.

C++ Nested For Loop Example

Let's see a simple example of nested for loop in C++.

  1. #include <iostream>  
  2. using namespace std;  
  3.    
  4. int main () {  
  5.         for(int i=1;i<=3;i++){      
  6.              for(int j=1;j<=3;j++){      
  7.             cout<<i<<" "<<j<<"\n";      
  8.           }     
  9.         }  
  10.     }    

Output:

1 1
1 2
1 3
2 1
2 2 
2 3
3 1
3 2
3 3

C++ Infinite For Loop

If we use double semicolon in for loop, it will be executed infinite times. Let's see a simple example of infinite for loop in C++.

  1. #include <iostream>  
  2. using namespace std;  
  3.    
  4. int main () {  
  5.         for (; ;)    
  6.           {    
  7.                   cout<<"Infinitive For Loop";    
  8.           }    
  9.     }    

Output:

Infinitive For Loop
Infinitive For Loop
Infinitive For Loop
Infinitive For Loop
Infinitive For Loop
ctrl+c

C++ While loop

In C++, while loop is used to iterate a part of the program several times. If the number of iteration is not fixed, it is recommended to use while loop than for loop.

  1. while(condition){    
  2. //code to be executed    
  3. }    

Flowchart:

Cpp While loop 1

C++ While Loop Example

Let's see a simple example of while loop to print table of 1.

  1. #include <iostream>  
  2. using namespace std;  
  3. int main() {         
  4.  int i=1;      
  5.          while(i<=10)   
  6.        {      
  7.             cout<<i <<"\n";    
  8.             i++;  
  9.           }       
  10.     }  

Output:

1
2
3
4
5
6
7
8
9
10

C++ Nested While Loop Example

In C++, we can use while loop inside another while loop, it is known as nested while loop. The nested while loop is executed fully when outer loop is executed once.

Let's see a simple example of nested while loop in C++ programming language.

  1. #include <iostream>  
  2. using namespace std;  
  3. int main () {  
  4.         int i=1;      
  5.           while(i<=3)     
  6.           {    
  7.               int j = 1;    
  8.               while (j <= 3)    
  9. {      
  10.             cout<<i<<" "<<j<<"\n";      
  11.             j++;  
  12.           }     
  13.            i++;  
  14.         }  
  15.     }    

Output:

1 1
1 2
1 3
2 1
2 2 
2 3
3 1
3 2
3 3

C++ Infinitive While Loop Example:

We can also create infinite while loop by passing true as the test condition.

  1. #include <iostream>  
  2. using namespace std;  
  3. int main () {  
  4.         while(true)  
  5.           {    
  6.                   cout<<"Infinitive While Loop";    
  7.           }    
  8.     }    

Output:

Infinitive While Loop 
Infinitive While Loop
Infinitive While Loop
Infinitive While Loop
Infinitive While Loop
ctrl+c

C++ Do-While Loop

The C++ do-while loop is used to iterate a part of the program several times. If the number of iteration is not fixed and you must have to execute the loop at least once, it is recommended to use do-while loop.

The C++ do-while loop is executed at least once because condition is checked after loop body.

  1. do{    
  2. //code to be executed    
  3. }while(condition);  

Flowchart:

Cpp Do while loop 1

C++ do-while Loop Example

Let's see a simple example of C++ do-while loop to print the table of 1.

  1. #include <iostream>  
  2. using namespace std;  
  3. int main() {  
  4.      int i = 1;    
  5.           do{    
  6.               cout<<i<<"\n";    
  7.               i++;    
  8.           } while (i <= 10) ;    
  9. }  

Output:

1
2
3
4
5
6
7
8
9
10

C++ Nested do-while Loop

In C++, if you use do-while loop inside another do-while loop, it is known as nested do-while loop. The nested do-while loop is executed fully for each outer do-while loop.

Let's see a simple example of nested do-while loop in C++.

  1. #include <iostream>  
  2. using namespace std;  
  3. int main() {  
  4.      int i = 1;    
  5.          do{    
  6.               int j = 1;          
  7.               do{    
  8.                 cout<<i<<"\n";        
  9.                   j++;    
  10.               } while (j <= 3) ;    
  11.               i++;    
  12.           } while (i <= 3) ;     
  13. }  

Output:

1 1
1 2
1 3
2 1
2 2 
2 3
3 1
3 2
3 3

C++ Infinitive do-while Loop

In C++, if you pass true in the do-while loop, it will be infinitive do-while loop.

  1. do{    
  2. //code to be executed    
  3. }while(true);  

C++ Infinitive do-while Loop Example

  1. #include <iostream>  
  2. using namespace std;  
  3. int main() {  
  4.       do{    
  5.               cout<<"Infinitive do-while Loop";    
  6.           } while(true);     
  7. }  

Output:

Infinitive do-while Loop 
Infinitive do-while Loop
Infinitive do-while Loop
Infinitive do-while Loop
Infinitive do-while Loop
ctrl+c

C++ Break Statement

The C++ break is used to break loop or switch statement. It breaks the current flow of the program at the given condition. In case of inner loop, it breaks only inner loop.

  1. jump-statement;      
  2. break;  

Flowchart:

Cpp Break statement 1

C++ Break Statement Example

Let's see a simple example of C++ break statement which is used inside the loop.

  1. #include <iostream>  
  2. using namespace std;  
  3. int main() {  
  4.       for (int i = 1; i <= 10; i++)    
  5.           {    
  6.               if (i == 5)    
  7.               {    
  8.                   break;    
  9.               }    
  10.         cout<<i<<"\n";    
  11.           }    
  12. }  

Output:

1
2
3
4

C++ Break Statement with Inner Loop

The C++ break statement breaks inner loop only if you use break statement inside the inner loop.

Let's see the example code:

  1. #include <iostream>  
  2. using namespace std;  
  3. int main()  
  4. {  
  5.     for(int i=1;i<=3;i++){        
  6.             for(int j=1;j<=3;j++){        
  7.                 if(i==2&&j==2){        
  8.                     break;        
  9.                         }        
  10.                     cout<<i<<" "<<j<<"\n";             
  11.                     }        
  12.           }    
  13. }  

Output:

1 1
1 2
1 3
2 1
3 1
3 2
3 3

C++ Continue Statement

The C++ continue statement is used to continue loop. It continues the current flow of the program and skips the remaining code at specified condition. In case of inner loop, it continues only inner loop.

  1. jump-statement;      
  2. continue;     

C++ Continue Statement Example

  1. #include <iostream>  
  2. using namespace std;  
  3. int main()  
  4. {  
  5.      for(int i=1;i<=10;i++){      
  6.             if(i==5){      
  7.                 continue;      
  8.             }      
  9.             cout<<i<<"\n";      
  10.         }        
  11. }  

Output:

1
2
3
4
6
7
8
9
10

C++ Continue Statement with Inner Loop

C++ Continue Statement continues inner loop only if you use continue statement inside the inner loop.

  1. #include <iostream>  
  2. using namespace std;  
  3. int main()  
  4. {  
  5.  for(int i=1;i<=3;i++){        
  6.             for(int j=1;j<=3;j++){        
  7.              if(i==2&&j==2){        
  8.                 continue;        
  9.                         }        
  10.                 cout<<i<<" "<<j<<"\n";                  
  11.                     }        
  12.             }            
  13. }  

Output:

1 1
1 2
1 3
2 1
2 3
3 1
3 2
3 3

C++ Goto Statement

The C++ goto statement is also known as jump statement. It is used to transfer control to the other part of the program. It unconditionally jumps to the specified label.

It can be used to transfer control from deeply nested loop or switch case label.

C++ Goto Statement Example

Let's see the simple example of goto statement in C++.

  1. #include <iostream>  
  2. using namespace std;  
  3. int main()  
  4. {  
  5. ineligible:    
  6.          cout<<"You are not eligible to vote!\n";    
  7.       cout<<"Enter your age:\n";    
  8.       int age;  
  9.       cin>>age;  
  10.       if (age < 18){    
  11.               goto ineligible;    
  12.       }    
  13.       else    
  14.       {    
  15.               cout<<"You are eligible to vote!";     
  16.       }         
  17. }  

Output:

You are not eligible to vote!
Enter your age:
16
You are not eligible to vote!
Enter your age:
7
You are not eligible to vote!
Enter your age:
22
You are eligible to vote!



Anurag Rana Educator CSE/IT

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