# Code Scrappers

## Categories of Function

For better understanding of arguments and return type in functions, user-defined functions can be categorized as:

• Function with no arguments and no return value
• Function with no arguments and return value
• Function with arguments but no return value
• Function with arguments and return value.

C programs to check if the number entered is prme or not

#### Function with no arguments and no return value.

```#include <stdio.h>

void prime();

void main()

{

prime();

}

void prime()

{

int n, i, count=0;

printf("Enter a positive integer:\n");

scanf("%d",&n);

for(i=2;i<=n/2;++i)

{

if(n%i==0)

{

count=1;

}

}

if (count==1)

{

printf("%d is not prime",n);

}
else

{

printf("%d is prime",n);

}
}

```

Function prime() is used for asking user a input, check for whether it is prime or not and display it accordingly. No argument is passed and returned form prime() function.

#### Function with no arguments but return value

```

#include <stdio.h>

int input();

void main()

{

int number,i;
int count = 0;

number=input();

for(i=2; i<=number/2; ++i)

{

if(number%i==0)

{

count = 1;

break;

}

}

if(count == 1)

{

printf("%d is not prime",number);

}
else

{
printf("%d is prime", number);
}

}

int input()

{

int n;

printf("Enter a positive integer:\n");

scanf("%d",&n);

return n;

}

```

There is no argument passed to input() function But, the value of n is returned from input() tomain() function.

#### Function with arguments and no return value

```
#include <stdio.h>

void prime(int n);

void main()

{

int number;

printf("Enter positive integer:\n");

scanf("%d",&number);

prime(number);

}

void prime(int n)

{
int i;
int count = 0;

for(i=2; i<=n/2; ++i)

{

if(n%i==0)

{

count = 1;

break;

}

}

if(count == 1)

{

printf("%d is not a prime number\n",n);

}
else

{

printf("%d is a prime number\n", n);

}
}

```

Here, prime() function is used for check whether it is prime or not and display it accordingly. Here, argument is passed to user-defined function but, value is not returned from it to calling function.

#### Function with argument and a return value

```
#include <stdio.h>

int check(int n);

void main()

{

int number,numbercheck=0;

printf("Enter positive number:\n");

scanf("%d",&number);

numbercheck=check(number);

if(numbercheck==1)

{

printf("%d is not prime",number);

}

else

{

printf("%d is prime",number);

}
}

int check(int n)

{

int i;

for(i=2;i<=n/2;++i)

{

if(n%i==0)

{
return 1;
}
}

return 0;

}

```

Here, check() function is used for checking whether a number is prime or not. In this program, input from user is passed to function check() and integer value is returned from it. If input the number is prime, 0 is returned and if number is not prime, 1 is returned.

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