Read
Improve
Improve
Improve
Like Article
Like
Save Article
Save
Report issue
Report
The Return statement in C/C++:
- C and C++ support return statements, which are also called jump statements.
- It is used to return a value from the function or stop the execution of the function. For more information on return statements, please refer to article return statement in C/C++ with examples.
There are two scenarios in which return statements will be used:
Method 1. Inside the main function:
- In this case, the return statement stops the execution of the program, and 0 or 1 will denote the execution status.
- These status codes will be just used as a convention for a long time in C language because the language does not support the objects and classes, and exceptions.
- return 0: A return 0 means that the program will execute successfully and did what it was intended to do.
- return 1: A return 1 means that there is some error while executing the program, and it is not performing what it was intended to do.
Important characteristics of the return statement:
- If exit with a status other than 0 then, print an error message to stderr.
- There are different conventions depending on the operating system about return codes.
- The Operating System may itself terminate the program with specific exit status codes if some invalid operations are performed.
Below is a program to illustrate the use of return 0 and return 1 inside the main function:
C++
// C++ program to divide two numbers
#include <iostream>
using namespace std;
// Driver Code
int main()
{
// Given integers
int a = 5, b = 0;
if (b == 0) {
// The below line is used to print
// the message in the error window
// fprintf(stderr, "Division by zero"
// " is not possible.");
// Print the error message
// as return is -1
printf("Division by zero is"
" not possible.");
return -1;
}
// Else print the division of
// two numbers
cout << a / b << endl;
return 0;
}
Output:
Division by zero is not possible.
Time Complexity: O(1)
Auxiliary Space: O(1)
Method 2. Inside the user-defined function:
- C++ treats boolean as a completely separate data type that has only 2 distinct values, i.e., true and false.
- The values 1 and 0 are of type int and are not implicitly convertible to boolean, that means:
- return 0: returning false from a function.
- return 1: returning true from a function.
Below is a program to illustrate the use of return 0 and return 1 inside the user-defined function:
C++
// C++ program to demonstrate the use
// of return 0 and return 1 inside
// user-defined function
#include <iostream>
using namespace std;
// Utility function returning 1 or
// 0 based on given age
int checkAdultUtil(int age)
{
if (age >= 18)
return 1;
else
return 0;
}
// Function to check for age
void checkAdult(int age)
{
// Checking on the basis
// of given age
if (checkAdultUtil(age))
cout << "You are an adult\n";
else
cout << "You are not an adult\n";
}
// Driver Code
int main()
{
// Given age
int age = 25;
// Function Call
checkAdult(age);
return 0;
}
Output:
You are an adult
Time Complexity: O(1)
Auxiliary Space: O(1)
Conclusion:
| Use-case | return 0 | return 1 |
| In the main function | return 0 in the main function means that the program executed successfully. | return 1 in the main function means that the program does not execute successfully and there is some error. |
| In user-defined function | return 0 means that the user-defined function is returning false. | return 1 means that the user-defined function is returning true. |
Learn to code easily with our course Coding for Everyone. This course is accessible and designed for everyone, even if you're new to coding. Start today and join millions on a journey to improve your skills!Whether you're preparing for your first job interview or aiming to upskill in this ever-evolving tech landscape, GeeksforGeeks Courses are your key to success. We provide top-quality content at affordable prices, all geared towards accelerating your growth in a time-bound manner. Join the millions we've already empowered, and we're here to do the same for you. Don't miss out - check it out now!
Last Updated : 20 Jun, 2022
Like Article
Save Article
Share your thoughts in the comments
