7.2用递归求两个数的最大公约数

#include <stdio.h>

int gcd( int m, int n );

void main()
{
int m,n,r;

scanf("%d%d",&m,&n);

r = gcd( m, n);

if ( r==0 )
printf("wrong/n");
else
printf("%d/n",r);
}

int gcd( int m, int n )
{
int r,temp;

if ( m<=0 || n<=0 )
return 0;
else
{
if ( m<n )
{
temp = n;
n = m;
m = temp;
}
r = m%n;
if ( r==0 )
{
r = n;

}
else
{
gcd( n, r );

}
return(r);
}
}