Find the errors in following function definitions :

1.

    def main()  
        print ("hello")
    

2.

   def func2():  
        print(2 + 3)
    

3.

   def compute():   
        print (x * x)
    

4.

   square (a)  
        return a * a  
   

1. Colon is missing at the end of function header.
2. There is no error.
3. The variable x is not defined.
4. def keyword at the beginning and colon at the end of function header are missing.

The corrected function definitions are:

1.

    def main():  
        print("hello")
   

2.

    def func2():  
        print(2 + 3)  
    

3.

    def compute(x):  
        print (x * x)  
    

4.

    def square(a):  
        return a * a