Question on for loop

Hi all, My question may sound silly but please bear with me , I am new at this. I am having trouble making a for loop output what I would like it to output.
In my code, the age of the user is passed as the second argument If the user is over 20 years old, I want to output "boy are you old!" once for year old over 20 that the user is.
Here is my code, the for loop I have only outputs the message once if the user enters a number 20 or over.

#include <stdio.h>
#include <string.h>

main (int argc, char **argv)
{
int n, age;

n = strlen(argv[1]);

if (n < 5)
printf("Your name is short\n");
printf("Your name is long\n");

age = atoi(argv[2]);

for (age = 20; age < 100; ++age);
{
printf("boy are you OLD!\n");
}
}

Thanks a lot.

#include <stdio.h>
#include <string.h> //for strlen()
#include <stdlib.h> //for atoi()
#include <conio.h> //for getch()

#line 1 /* makes the first line: 'void main(...)' help Debuging process. good programming pratice */
void main (int argc, char **argv){

unsigned short n, age;
n = strlen(argv[1]);
age = atoi(argv[2]);
if (n < 5) {
printf("Your name is short\n");
}
if(n > 5){
printf("Your name is long\n");
}
if(age > 20){
for (; age <= 100; ++age){
printf("boy are you OLD!\n");
}
}else{
printf("boy you're YOUNG\n");
}
getch();
}[FONT=arial]

> 'void main(...)'
God, don't use that.

My compiler screams at me for even having it in there.

[edit]
Pleaase use code tags.
Use int main(void)
return 0; at the end of main.
...and if you think void main is good, please don't help anybody.
[/edit]

anatazi, possibly you could refer to this for command line stuff:

Code:

---

/*

        Program:
        CmdLine.c
       
        Purpose:
        Demonstrates the use of command line parameters.

*/

#include <stdio.h>

void default_message(void);

int main( int argc, char * argv[] ) 
{
        if (argc == 2)
        {
                if(argv[1][0] == '?')
                {
                        printf("Help stuff would go here.\n");
                }
                else
                {
                        printf("%s \n", argv[1]);
                }
        }
        else if ( argc >= 3 )
        {
                printf("Invalid input:\n");
                printf("Only one command-line parameter allowed.\n");
        }
        else
        {
                default_message();
        }
        return 0;
}

void default_message(void)
{
        printf("CmdLine.exe:\n");
        printf("The purpose of this program is to demonstrate command line arguments.\n");
        printf("This program will print whatever you type on the screen.\n\n");
        printf("Example:\n");
        printf("C:\\>CmdLine.exe Hmmm\n");
        printf("Hmmm\n");
}

---

This just demonstrates command line arguments, i'll leave the age stuff to you.

Thanks for the help, I finally got it to work!