练习11-1

#include

int main(void){

char *p = "123";

printf("p=\"%s\"\n", p);

p = "456";

printf("p=\"%s\"\n", p);

return 0;

}

练习11-2

#include

int count(const char*c){

int n = 0;

while (*c++)

n++;

return n;

}

int main(void)

{

int i;

int n = 0;

char a[][5] = { "LISP", "C", "Ada" };

char *p[] = { "PAUL", "X", "MAC" };

for (i = 0; i

printf("a[%d] = \"%s\"\n", i, a[i]);

for (i = 0; i < count(p); i++)

printf("p[%d] = \"%s\"\n", i, p[i]);

return 0;

}练习11-3

#include

char *str_copy(char *d, const char *s)

{

char *t = d;

while (*d++ = *s++)

;

return t;

}

int main(void)

{

char str[128] = "ABC";

char tmp[128];

printf("str = \"%s\"\n", str);

printf("复制的是：", tmp);

scanf("%s", tmp);

puts("复制了。");

printf("str = \"%s\"\n", str_copy(str, tmp));

return 0;

}练习11-4

#include

void put_string (const char *s)

{

while (*s)

putchar(*s++);

}

int main(void)

{

char str[128] = "ABC";

put_string(str);

return 0;

}练习11-5

#include

int str_chnum(const char *s, int c)

{

int n = 0;

while (*s){

if (*s == c)

n++;

*s++;

}

return (n);

}

int main(void)

{

char ch='d';

char str[128] = "ABBBBBBBBBBBBBBBCCCCCCCCCCCCCAAAAAAAAAAAAAAAAC";

printf("C的个数是：%d",str_chnum(str,ch));

return 0;

}练习11-7

#include

#include

void str_toupper(char *s)

{

int i = 0;

while (*s) {

*s = toupper(*s);

*s++;

}

}

void str_tolower(char *s)

{

int i = 0;

while (s) {

s[i] = tolower(s[i]);

i++;

}

}

int main(void)

{

char str[128];

printf("请输入字符串：");

scanf("%s", str);

str_toupper(str);

printf("大写字母：%s\n", str);

str_tolower(str);

printf("小写字母：%s\n", str);

return 0;

}

练习11-8

# include

void del_digit(char *str)

{

char *p = str;

while (*p)

if (*p >= '0' && *p <= '9')

p++;

else

*str++ = *p++;

*str = '\0';

}

int main(void){

char str[128];

printf("请输入字符串：");

scanf("%s", str);

del_digit(str);

printf("删除数字后为：%s", str);

return 0;

}