# Python | Function classifications on the basis of parameters and return values

Python function classifications: Here, we are going to learn about the python function classifications based on their parameters and return values.
Submitted by Pankaj Singh, on October 11, 2018

There are following types of the functions based on their parameters and return values:

1. Function with no argument and no return value
2. Function with no argument but return value
3. Function with argument and no return value
4. Function with arguments and return value

### 1) Function with no argument and no return value

```def sum():
a = int(input("Enter A: "))
b = int(input("Enter B: "))
c=a+b
print("Sum    :", c)

def main():
sum()

if __name__=="__main__":
main()
```

Output

```Enter A: 10
Enter B: 20
Sum    : 30
```

### 2) Function with no argument but return value

```def sum():
a = int(input("Enter A: "))
b = int(input("Enter B: "))
c=a+b
return c

def main():
c = sum()
print("Sum    :",c)

if __name__=="__main__":
main()
```

Output

```Enter A: 10
Enter B: 20
Sum    : 30
```

### 3) Function with argument and no return value

```def sum(a,b):
c=a+b
print("Sum    :", c)

def main():
a = int(input("Enter A: "))
b = int(input("Enter B: "))
sum(a,b)

if __name__=="__main__":
main()
```

Output

```Enter A: 10
Enter B: 20
Sum    : 30
```

### 4) Function with arguments and return value

```def sum(a,b):
c=a+b
return c

def main():
a = int(input("Enter A: "))
b = int(input("Enter B: "))
c = sum(a,b)
print("Sum    :",c)

if __name__=="__main__":
main()
```

Output

```Enter A: 10
Enter B: 20
Sum    : 30
```