Prog#189: transfer a file into another

/*
transfer a file into another
Program#189
*/
#include<stdio.h>
main(int argc,char *argv[])
{
char a;
FILE *fs,*ft;
if(argc!=3)
{
printf("error. no.of arg.");
return 0;
}
fs=fopen (argv[1], "r");
if(fs==NULL)
{
printf("file open error");
return 0;
}
ft=fopen (argv[2], "w");
if(ft==NULL)
{
printf("file open error");
return 0;
}
while((a=getc(fs))!=EOF)
{
if(a>=65 && a<=90)
a+=32;
putc(a, ft);
}
fclose(fs);
fclose(ft);
}