c語言輸入一段英文把英文的每個英文字單獨印成一行

char buf[] ="This a sample string.";

char *tok_string = " ";
char *token = strtok(buf, tok_string);
while( token != NULL ){
printf("%s\n", token);
token = strtok(NULL, tok_string);
}

You can use stktok().

課本就有...