Check whether the given number is positive or negative or 0 in C++

Check whether the given number is positive or negative or 0 in C++

In this tutorial, we will discuss the  Check whether the given number is positive or negative or 0 in C++

In this post, we are going to learn how to check whether the given number is positive or Negative or zero  using 5 ways in C++ language

 

The logic to check positive, negative or zero

• Check the condition if(num<0), then number is negative
• Check the condition if(num>0), then number is positive
• Check the condition if(num==0), then number is zero

 

Check whether the given number is positive or negative or 0

Code to find whether the given number is positive or negative or 0 – using if else

Program 1

#include <iostream>
#include <conio.h>
using namespace std;

int main()
{
    int num=-100;

  if(num>0){
 cout<<num<<" is a positive number";
}else if(num<0){

  cout<<num<<" is a negative number";
}
else{
  cout<<"The given number is zero";
}
getch();
    return 0;
}

When the above code is executed, it produces the following result

-100 is a negative number

In this program,

• integer variables num  is declared and initialized
• The given numbers are tested whether it is positive, negative or zero using if- else statements
• Then,the program is displayed the output of using cout<<

 

Code to find whether the given number is positive or negative or 0 -Entered by user

Program 2

#include <iostream>
#include <conio.h>
using namespace std;

int main()
{
    int num;
    cout<<"Enter a number: ";
    cin>>num;

  if(num>0){
 cout<<num<<" is a positive number";
}else if(num<0){

  cout<<num<<" is a negative number";
}
else{
  cout<<"The given number is zero";
}
getch();
    return 0;
}

When the above code is executed, it produces the following result

Case 1

Enter a number: 4321
4321 is a positive number

Case 2

Enter a number:-7891
-7891 is a negative number

Case 3

Enter any number: 0
the given number is zero

 

Approach

• integer variable num is declared.
• The program asks input from the user
• Then the user enters the input values for num.
• The program will read the input using cin>> and store to the variable num
• The given number is tested whether it is positive, negative or zero using if- else statements
• Then,the program is displayed the output of using cout<< ,

 

Code to find whether the given number is positive or negative or 0 – using Nested if

Program 3

#include <iostream>
#include <conio.h>
using namespace std;

int main()
{
    int num;
    cout<<"Enter a number : \n";
    cin>>num;

  if(num<=0){

 if(num==0){

 cout<<num<<"you entered zero";
}
else{
  cout<<"you entered a negative number";
}
  }
else{
  cout<<"you entered a positive number";
}

getch();
    return 0;
}

When the above code is executed, it produces the following result

Case 1

Enter a number:
5678
You entered a positive number

Case 2

Enter a number:
-765
You entered a negative number

Case 3

Enter a number:
0
You entered zero

 

Approach

• integer variable num is declared.
• The program asks input from the user
• Then the user enters the input values for num.
• The program will read the input using cin>> and store to the variable num
• The given number is tested whether it is positive, negative or zero using Nested if- else statements
• Then,the program is displayed the output of using cout<< ,

Code to find whether the given number is positive or negative or 0 – using switch case

Program 4

#include <iostream>
#include <conio.h>
using namespace std;

int main()
{
    int num;
    cout<<"Enter any number\n";
    cin>>num;

    switch(num>0){
case 1://check  num is positive
    cout<<num<<" is a positive number";
    break;

case 0://num is either negative or zero
    switch(num<0){
    case 1://check  num is negative
    cout<<num<<" is a negative number";
    break;

case 0://check  num is negative
    cout<<"you entered zero";
    break;
    }
    break;
    }
    getch();
    return 0;
}

When the above code is executed, it produces the following result

Case 1

Enter any number
1000
1000 is a positive number

Case 2

Enter any number
-789
-789 is a negative number

Case 3

Enter any number
0
you entered zero

 

Approach

• integer variable num is declared.
• The program asks input from the user
• Then the user enters the input values for num.
• The program will read the input using cin>> and store to the variable num
• The given number is tested whether it is positive, negative or zero using switch case statements
• Then,the program is displayed the output of using cout<< ,

 

Code to find whether the given number is positive or negative or 0 – using function

Program 5

#include <iostream>
#include <conio.h>
using namespace std;

#include <stdlib.h>
int findPosNeg(int);//function prototype
int main()
{
    int num;
   cout<<"Enter a integer number:";
    cin>>num;
  //read input from the user
findPosNeg(num);//function call
getch();
    return 0;
}

findPosNeg(int num){//function definition
if(num<=0){
if(num==0){
        cout<<"you entered zero";
}else{
  cout<<num<<" is a Negative number";
}
}
else{
   cout<<num<<" is a Positive number";
}
}

When the above code is executed, it produces the following result

case 1

Enter a integer number:675
675 is a positive number

case 2

Enter a integer number: -786
-786 is a Negative number

case 3

Enter a integer number: 0
you entered zero

 

Approach

• Declare a function named as findPosNeg(int); with parameter
• integer variables num is declared.
• The program asks input from the user
• Then the user enters the input values for num.
• The program will read the input using cin>> and store the variable num.
• Define the function  findPosNeg(); to find whether the number is Negative or Positive or zero
• Call the function to produce output
• finally, the program displays the output using cout<<.

 

 

Suggested for you

if statements in C++ language

Nested if in C++ language

Operator in C++ language

Switch case in C++ language

 

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