C primer plus(第六版）第十一章源代码
#include
#define MSG "I am a symbolic string constant."
#define MAXLENGTH 81
int main(void)
{
char words[MAXLENGTH] = "I am a string in an array.";
const char *pt1 = "Something is pointing at me.";
puts("Here are some strings:");
puts(MSG);
puts(words);
puts(pt1);
words[8] = 'p';
puts(words);
return 0;
}
#include
int main(void)
{
printf("%s, %p, %c\n", "We", "are", *"space farers");
return 0;
}
#define MSG "I'm special"
#include
int main(void)
{
char ar[] = MSG;
const char *pt = MSG;
printf("address of \"I'm special\": %p \n", "I'm special");
printf(" address ar: %p\n", ar);
printf(" address pt: %p\n", pt);
printf(" address of MSG: %p\n", MSG);
printf("address of \"I'm special\": %p \n", "I'm special");
return 0;
}
#include
#define SLEN 40
#define LIM 5
int main(void)
{
const char *mytalents[LIM] = {
"Adding numbers swiftly",
"Multiplying accurately", "Stashing data",
"Following instructions to the letter",
"Understanding the C language"
};
char yourtalents[LIM][SLEN] = {
"Walking in a straight line",
"Sleeping", "Watching television",
"Mailing letters", "Reading email"
};
int i;
puts("Let's compare talents.");
printf("%-36s %-25s\n", "My Talents", "Your Talents");
for (i = 0; i < LIM; i++)
printf("%-36s %-25s\n", mytalents[i], yourtalents[i]);
printf("\nsizeof mytalents: %zd, sizeof yourtalents: %zd\n",
sizeof(mytalents), sizeof(yourtalents));
return 0;
}
#include
int main(void)
{
const char *mesg = "Don't be a fool!";
const char *copy;
copy = mesg;
printf("%s\n", copy);
printf("mesg = %s; &mesg = %p; value = %p\n", mesg, &mesg, mesg);
printf("copy = %s; © = %p; value = %p\n", copy, ©, copy);
return 0;
}
#include
#define STLEN 81
int main(void)
{
char words[STLEN];
puts("Enter a string, please.");
gets(words);
printf("Your string twice:\n");
printf("%s\n", words);
puts(words);
puts("Done.");
return 0;
}
#include
#define STLEN 14
int main(void)
{
char words[STLEN];
puts("Enter a string, please.");
fgets(words, STLEN, stdin);
printf("Your string twice (puts(), then fputs()):\n");
puts(words);
fputs(words, stdout);
puts("Enter another string, please.");
fgets(words, STLEN, stdin);
printf("Your string twice (puts(), then fupts()):\n");
puts(words);
fputs(words, stdout);
puts("Done.");
return 0;
}
#include
#define STLEN 10
int main(void)
{
char words[STLEN];
puts("Enter strings (empty line to quit):");
while (fgets(words, STLEN, stdin) != NULL && words[0] != '\n')
fputs(words, stdout);
puts("Done.");
return 0;
}
#include
#define STLEN 10
int main(void)
{
char words[STLEN];
int i;
puts("Enter strings (empty line to quit):");
while (fgets(words, STLEN, stdin) != NULL && words[0] != '\n')
{
i = 0;
while (words[i] != '\n' && words[i] != '\0')
i++;
if (words[i] == '\n')
words[i] = '\0';
else
while (getchar() != '\n')
continue;
puts(words);
}
puts(words);
return 0;
}
char * s_gets(char *st, int n)
{
char *ret_val;
int i = 0;
ret_val = fgets(st, n, stdin);
if (ret_val)
{
while (st[i] != '\n' && st[i] != '\0')
i++;
if (st[i] == '\n')
st[i] = '\0';
else
while (getchar() != '\n')
continue;
}
return ret_val;
}
#include
int main(void)
{
char name1[11], name2[11];
int count;
printf("Please enter 2 names.\n");
count = scanf("%5s %10s", name1, name2);
printf("I read the %d names %s and %s.\n", count, name1, name2);
return 0;
}
#include
#define DEF "I am a #defined string."
int main(void)
{
char str1[80] = "An array was initialized to me.";
const char *str2 = "A pointer was initialized to me.";
puts("I'm an argument to puts().");
puts(DEF);
puts(str1);
puts(str2);
puts(&str1[5]);
puts(str2+4);
return 0;
}
#include
int main(void)
{
char side_a[] = "Side A";
char dont[] = { 'W', 'O', 'W', '!' };
char side_b[] = "Side B";
puts(dont);
return 0;
}
#include
void put1(const char * string)
{
while (*string != '\0')
putchar(*string++);
}
#include
int put2(const char * string)
{
int count = 0;
while (*string)
{
putchar(*string++);
count++;
}
putchar('\n');
return (count);
}
#include
void put1(const char *);
int put2(const char *);
int main(void)
{
put1("If I'd as much money");
put1(" as I could spend,\n");
printf("I count %d characters.\n",
put2("I never would cry old chairs to mend."));
return 0;
}
void put1(const char * string)
{
while (*string != '\0')
putchar(*string++);
}
int put2(const char * string)
{
int count = 0;
while (*string)
{
putchar(*string++);
count++;
}
putchar('\n');
return (count);
}
#include
#include
void fit(char *, unsigned int);
int main(void)
{
char mesg[] = "Things should be as simple as possible,"
" but not simpler.";
puts(mesg);
fit(mesg, 38);
puts(mesg);
puts("Let's look at some more of the string.");
puts(mesg + 39);
return 0;
}
void fit(char *string, unsigned int size)
{
if (strlen(string) > size)
string[size] = '\0';
}
#include
#include
#define SIZE 80
char * s_gets(char * st, int n);
int main(void)
{
char flower[SIZE];
char addon[] = "s smell like old shoes.";
puts("What is your favourite flower?");
if (s_gets(flower, SIZE))
{
strcat(flower, addon);
puts(flower);
puts(addon);
}
else
puts("End of file encountered!");
puts("bye");
return 0;
}
char * s_gets(char *st, int n)
{
char *ret_val;
int i = 0;
ret_val = fgets(st, n, stdin);
if (ret_val)
{
while (st[i] != '\n' && st[i] != '\0')
i++;
if (st[i] == '\n')
st[i] = '\0';
else
while (getchar() != '\0')
continue;
}
return ret_val;
}
#include
#include
#define SIZE 30
#define BUGSIZE 13
char * s_gets(char * st, int n);
int main(void)
{
char flower[SIZE];
char addon[] = "s smell like old shoes.";
char bug[BUGSIZE];
int available;
puts("What is your favourite flower?");
s_gets(flower, SIZE);
if ((strlen(addon) + strlen(flower) + 1) <= SIZE)
strcat(flower, addon);
puts(flower);
puts("What is your favourite bug?");
s_gets(bug, BUGSIZE);
available = BUGSIZE - strlen(bug) - 1;
strncat(bug, addon, available);
puts(bug);
return 0;
}
char * s_gets(char *st, int n)
{
char *ret_val;
int i = 0;
ret_val = fgets(st, n, stdin);
if (ret_val)
{
while (st[i] != '\n' && st[i] != '\0')
i++;
if (st[i] == '\n')
st[i] = '\0';
else
while (getchar() != '\n')
continue;
}
return ret_val;
}
#include
#define ANSWER "Grant"
#define SIZE 40
char * s_gets(char * st, int n);
int main(void)
{
char try_try[SIZE];
puts("Who is buried in Grant's tomb?");
s_gets(try_try, SIZE);
while (try_try != ANSWER)
{
puts("No, that's wrong. try_try again.");
s_gets(try_try, SIZE);
}
puts("That's right!");
return 0;
}
char * s_gets(char *st, int n)
{
char *ret_val;
int i = 0;
ret_val = fgets(st, n, stdin);
if (ret_val)
{
while (st[i] != '\n' && st[i] != '\0')
i++;
if (st[i] == '\n')
st[i] = '\0';
else
while (getchar() != '\n')
continue;
}
return ret_val;
}
#include
#include
#define ANSWER "Grant"
#define SIZE 40
char * s_gets(char * st, int n);
int main(void)
{
char try_try[SIZE];
puts("Who is buried in Grant's tomb?");
s_gets(try_try, SIZE);
while (strcmp(try_try, ANSWER) != 0)
{
puts("No, that's wrong. try again.");
s_gets(try_try, SIZE);
}
puts("That's right!");
return 0;
}
char * s_gets(char *st, int n)
{
char *ret_val;
int i = 0;
ret_val = fgets(st, n, stdin);
if (ret_val)
{
while (st[i] != '\n' && st[i] != '\0')
i++;
if (st[i] == '\n')
st[i] = '\0';
else
while (getchar() != '\n')
continue;
}
return ret_val;
}
#include
#include
int main(void)
{
printf("strcmp(\"A\", \"A\") is ");
printf("%d\n", strcmp("A", "A"));
printf("strcmp(\"A\", \"B\") is ");
printf("%d\n", strcmp("A", "B"));
printf("strcmp(\"B\", \"A\") is ");
printf("%d\n", strcmp("B", "A"));
printf("strcmp(\"C\", \"A\") is ");
printf("%d\n", strcmp("C", "A"));
printf("strcmp(\"Z\", \"a\") is ");
printf("%d\n", strcmp("Z", "a"));
printf("strcmp(\"apples\", \"apple\") is ");
printf("%d\n", strcmp("apples", "apple"));
return 0;
}
#include
#include
#define SIZE 80
#define LIM 10
#define STOP "quit"
char * s_gets(char * st, int n);
int main(void)
{
char input[LIM][SIZE];
int ct = 0;
printf("Enter up to %d lines (type quit to quit):\n", LIM);
while (ct < LIM && s_gets(input[ct], SIZE) != NULL &&
strcmp(input[ct], STOP) != 0)
{
ct++;
}
printf("%d strings entered\n", ct);
return 0;
}
char * s_gets(char *st, int n)
{
char *ret_val;
int i = 0;
ret_val = fgets(st, n, stdin);
if (ret_val)
{
while (st[i] != '\n' && st[i] != '\0')
i++;
if (st[i] == '\n')
st[i] = '\0';
else
while (getchar() != '\n')
continue;
}
return ret_val;
}
#include
#include
#define LISTSIZE 6
int main()
{
const char * list[LISTSIZE] =
{
"astronomy", "astounding",
"astrophysics", "ostracize",
"asterism", "astrophobia"
};
int count = 0;
int i;
for (i = 0; i < LISTSIZE; i++)
if (strncmp(list[i], "astro", 5) == 0)
{
printf("Found: %s\n", list[i]);
count++;
}
printf("The list contained %d words beginning"
" with astro.\n", count);
return 0;
}
#include
#include
#define SIZE 40
#define LIM 5
char * s_gets(char * st, int n);
int main(void)
{
char qwords[LIM][SIZE];
char temp[SIZE];
int i = 0;
printf("Enter %d words beginning with q:\n", LIM);
while (i < LIM && s_gets(temp, SIZE))
{
if (temp[0] != 'q')
printf("%s doesn't begin with q!\n", temp);
else
{
strcpy(qwords[i], temp);
i++;
}
}
puts("Here are the words accepted:");
for (i = 0; i < LIM; i++)
puts(qwords[i]);
return 0;
}
char * s_gets(char *st, int n)
{
char *ret_val;
int i = 0;
ret_val = fgets(st, n, stdin);
if (ret_val)
{
while (st[i] != '\n' && st[i] != '\0')
i++;
if (st[i] == '\n')
st[i] = '\0';
else
while (getchar() != '\n')
continue;
}
return ret_val;
}
#include
#include
#define WORDS "beast"
#define SIZE 40
int main(void)
{
const char * orig = WORDS;
char copy[SIZE] = "Be the best that you can be.";
char * ps;
puts(orig);
puts(copy);
ps = strcpy(copy + 7, orig);
puts(copy);
puts(ps);
return 0;
}
#include
#include
#define SIZE 40
#define TARGSIZE 7
#define LIM 5
char * s_gets(char * st, int n);
int main(void)
{
char qwords[LIM][TARGSIZE];
char temp[SIZE];
int i = 0;
printf("Enter %d words beginning with q:\n", LIM);
while (i < LIM && s_gets(temp, SIZE))
{
if (temp[0] != 'q')
printf("%s doesn't begin with q!\n", temp);
else
{
strncpy(qwords[i], temp, TARGSIZE - 1);
qwords[i][TARGSIZE - 1] = '\0';
i++;
}
}
puts("Here are the words accepted:");
for (i = 0; i < LIM; i++)
puts(qwords[i]);
return 0;
}
char * s_gets(char *st, int n)
{
char *ret_val;
int i = 0;
ret_val = fgets(st, n, stdin);
if (ret_val)
{
while (st[i] != '\n' && st[i] != '\0')
i++;
if (st[i] == '\n')
st[i] = '\0';
else
while (getchar() != '\n')
continue;
}
return ret_val;
}
#include
#define MAX 20
char * s_gets(char * st, int n);
int main(void)
{
char first[MAX];
char last[MAX];
char formal[2 * MAX + 10];
double prize;
puts("Enter your first name:");
s_gets(first, MAX);
puts("Enter your last name:");
s_gets(last, MAX);
puts("Enter your prize money:");
scanf("%lf", &prize);
sprintf(formal, "%s, %-19s: $%6.2f\n", last, first, prize);
puts(formal);
return 0;
}
char * s_gets(char *st, int n)
{
char *ret_val;
int i = 0;
ret_val = fgets(st, n, stdin);
if (ret_val)
{
while (st[i] != '\n' && st[i] != '\0')
i++;
if (st[i] == '\n')
st[i] = '\0';
else
while (getchar() != '\n')
continue;
}
return ret_val;
}
#include
#include
#define SIZE 81
#define LIM 20
#define HALT ""
void stsrt(char *strings[], int num);
char * s_gets(char * st, int n);
int main(void)
{
char input[LIM][SIZE];
char *ptstr[LIM];
int ct = 0;
int k;
printf("Input up to %d lines, and i will sort them.\n", LIM);
printf("To stop, press the Enter key at a line's start.\n");
while (ct < LIM && s_gets(input[ct], SIZE) != NULL
&& input[ct][0] != '\0')
{
ptstr[ct] = input[ct];
ct++;
}
stsrt(ptstr, ct);
puts("\nHere's the sorted list:\n");
for (k = 0; k < ct; k++)
puts(ptstr[k]);
return 0;
}
void stsrt(char *strings[], int num)
{
char *temp;
int top, seek;
for (top = 0; top < num - 1; top++)
for (seek = top + 1; seek < num; seek++)
if (strcmp(strings[top], strings[seek]) > 0)
{
temp = strings[top];
strings[top] = strings[seek];
strings[seek] = temp;
}
}
char * s_gets(char * st, int n)
{
char * ret_val;
int i = 0;
ret_val = fgets(st, n, stdin);
if (ret_val)
{
while (st[i] != '\n' && st[i] != '\0')
i++;
if (st[i] == '\n')
st[i] = '\0';
else
while (getchar() != '\n')
continue;
}
return ret_val;
}
#include
#include
#include
#define LIMIT 81
void ToUpper(char *);
int PunctCount(const char *);
int main(void)
{
char line[LIMIT];
char * find;
puts("Please enter a line:");
fgets(line, LIMIT, stdin);
find = strchr(line, '\n');
if (find)
*find = '\0';
ToUpper(line);
puts(line);
printf("That line has %d punctuation characters.\n", PunctCount(line));
return 0;
}
void ToUpper(char * str)
{
while (*str)
{
*str = toupper(*str);
str++;
}
}
int PunctCount(const char * str)
{
int ct = 0;
while (*str)
{
if (ispunct(*str))
ct++;
str++;
}
return ct;
}
#include
int main(int argc, char *argv[])
{
int count;
printf("The command line has %d arguments:\n", argc -1);
for (count = 1; count < argc; count++)
printf("%d: %s\n", count, argv[count]);
printf("\n");
return 0;
}
#include
#include
int main(int argc, char *argv[])
{
int i, times;
if (argc < 2 || (times = atoi(argv[1])) < 1)
printf("Usage: %s positive-number\n", argv[0]);
else
for (i = 0; i < times; i++)
puts("Hello, good looking!");
return 0;
}
#include
#include
#define LIM 30
char * s_gets(char * st, int n);
int main()
{
char number[LIM];
char * end;
long value;
puts("Enter a number (empty line to quit):");
while (s_gets(number, LIM) && number[0] != '\0')
{
value = strtol(number, &end, 10);
printf("base 10 input, base 10 output: %ld, stopped at %s (%d)\n",
value, end, *end);
value = strtol(number, &end, 16);
printf("base 16 input, base 10 output: %ld, stopped at %s (%d)\n",
value, end, *end);
puts("Next number:");
}
puts("Bye!\n");
return 0;
}
char * s_gets(char * st, int n)
{
char * ret_val;
int i = 0;
ret_val = fgets(st, n, stdin);
if (ret_val)
{
while (st[i] != '\n' && st[i] != '\0')
i++;
if (st[i] == '\n')
st[i] = '\0';
else
while (getchar() != '\n')
continue;
}
return ret_val;
}
