int main(int argc, char *argv[])
{
int x; //<=== missing semicolon
for (x=0;x<5;x++) printf("Hello, world!\n") ;
for (x=1;x<=10;x++) printf("Counting: %d\n", x) ;
for (x='a';x<='z';x++) printf("alphabet: %c\n", x) ;
for (x='A';x<='Z';x++) printf("ALPHABET: %c\n", x) ;
return 0;
}
Maybe you want to google around for a C programming tutorial.