1 #include <stdio.h> 2 3 int main(void)4 main(void) { 5 int ch; 6 int done = 0; 7 8 while ((ch = getchar()) != EOF) { 9 if (isdigit((unsigned char)ch)) { 10 done = 1; 11 goto done; 12 } 13 } 14 done: 15 if (done) putchar(ch); 16 else puts("premature end of loop"); 17 return 0; 18 } 19 20