C Primer Plus 第六版 第11章 编程答案
1.第1题
#include
#define SIZE 10
char * getnchar(char *, int);
int main(void)
{
char st[SIZE];
char * sts;
printf("请输入:");
sts = getnchar(st, SIZE - 1);
if (sts == NULL)
puts("输入失败");
else
puts(st);
return 0;
}
char * getnchar(char * st, int n)
{
int i;
int ch;
for (i = 0 ; i < n; i++)
{
ch = getchar();
if (ch == EOF)
break;
else
st[i] = ch;
}
if (ch == EOF)
return NULL;
else
{
st[i] = '\0';
return st;
}
}
2.第2题
#include
#define SIZE 10
char * getnchar(char * st, int n);
int main(void)
{
char st[SIZE];
char * sts;
printf("请输入:");
sts = getnchar(st, SIZE-1);
if (sts == NULL)
puts("输入失败");
else
puts(st);
return 0;
}
char * getnchar(char * st, int n)
{
int i;
int ch;
for (i = 0; i < n; i++)
{
ch = getchar();
if (ch == EOF || ch == '\n' || ch == ' ' || ch ==' ')
break;
else
st[i] = ch;
}
if (ch == EOF)
return NULL;
else
{
st[i] = '\0';
return st;
}
}
3.第3题
#include
#define SIZE 10
char * getnchar(char * st, int n);
int main(void)
{
char st[SIZE];
char * sts;
printf("请输入");
sts = getnchar(st, SIZE - 1);
if (sts == NULL)
puts("输入错误");
else
puts(sts);
return 0;
}
char * getnchar(char * st, int n)
{
int i;
int ch;
while ((ch = getchar()) == ' ' || ch == ' ' || ch == '\n')
continue;
for (i = 0; i < n; i++)
{
if (ch == EOF || ch == ' ' || ch == ' ' || ch == '\n')
break;
else
st[i] = ch;
ch = getchar();
}
if (ch == EOF)
return NULL;
else
{
st[i] = '\0';
return st;
}
}
4.第4题
#include
#define SIZE 10
char * getnchar(char * st, int n);
int main(void)
{
char st[SIZE];
char * sts;
printf("请输入");
sts = getnchar(st, SIZE - 1);
if (sts == NULL)
puts("输入错误");
else
puts(sts);
return 0;
}
char * getnchar(char * st, int n)
{
int i;
int ch;
while ((ch = getchar()) == ' ' || ch == ' ' || ch == '\n')
continue;
for (i = 0; i < n; i++)
{
if (ch == EOF || ch == ' ' || ch == ' ' || ch == '\n')
break;
else
st[i] = ch;
ch = getchar();
}
if (ch == EOF)
return NULL;
else
{
st[i] = '\0';
return st;
}
}
5.第5题
#include
char * strchrs(char * s, int c);
int main(void)
{
char * sts;
char st[] = "abcdefg\n\0";
if (sts = strchrs(st, '\n'));
*sts = 'A';
puts(st);
return 0;
}
char * strchrs(char * s, int c)
{
while (*s)
{
if (*s == c)
return s;
else
s++;
}
if (*s == c)
return s;
else
return NULL;
}
6.第6题
#include
#include
#define SIZE 100
char * s_gets(char * st, int n);
int is_within(char * s, int c);
int main(void)
{
char st[SIZE];
int ch;
puts("请输入字符串");
while (s_gets(st, SIZE) && st[0] != '\0')
{
puts("请输入字符");
ch = getchar();
while (getchar() != '\n');
if (is_within(st, ch))
puts("存在");
else
puts("不存在");
puts("请输入字符串");
}
return 0;
}
int is_within(char * s, int c)
{
if (strchr(s, c))
return 1;
else
return 0;
}
char * s_gets(char * st, int n)
{
char * ret_val;
char * find;
ret_val = fgets(st, n, stdin);
if (ret_val)
{
if (find = strchr(st, '\n'))
*find = '\0';
else
while (getchar() != '\n');
}
return ret_val;
}
7.第7题
#include
#include
#define SIZE 10
char * mystrncpy(char * s1, char * s2, int n);
char * s_gets(char * st, int n);
int main(void)
{
char st[SIZE];
char sts[SIZE];
int ch;
puts("请输入字符串");
while (s_gets(st, SIZE) && st[0] != '\0')
{
puts("请输入n");
scanf("%d",&ch);
while (getchar() !='\n');
mystrncpy(sts, st, ch);
puts(sts);
puts("请输入字符串");
}
return 0;
}
char * mystrncpy(char * s1, char * s2, int n)
{
int i;
int len;
len = strlen(s1);
for ( i = 0; i < len; i++)
{
s1[i] = '\0';
}
for (i = 0; i < n-1; i++)
{
s1[i] = s2[i];
}
if (strlen(s2) < n)
s1[i] = '\0';
else
s1[i] = s2[i];
return s1;
}
char * s_gets(char * st, int n)
{
char * ret_val;
char * find;
ret_val = fgets(st, n, stdin);
if (ret_val)
{
if (find = strchr(st, '\n'))
*find = '\0';
else
while (getchar() != '\n');
}
return ret_val;
}
8.第8题
#include
#include
char * string_in(const char * s1, const char * s2);
int main(void)
{
char s1[100];
char s2[100];
printf("请输入s1：");
while (scanf("%s",&s1) == 1)
{
printf("请输入s2：");
scanf("%s",&s2);
if (string_in(s1,s2) != NULL)
puts("包含");
else
puts("不包含");
printf("请输入s1：");
}
return 0;
}
char * string_in(const char * s1, const char * s2)
{
int l2;
int j = 1;
int i;
l2 = strlen(s2);
i = strlen(s1) + 1 - l2;
if (i > 0)
while ((j = strncmp(s1,s2,l2)) && i--)
s1++;
if (j)
return NULL;
else
return (char *)s1;
}
9.第9题
#include
#include
void fan(char *);
int main(void)
{
char s1[100];
printf("请输入s1:");
while (scanf("%s",&s1) == 1)
{
fan(s1);
puts(s1);
printf("请输入s1:");
}
return 0;
}
void fan(char * s1)
{
int i = 0;
int j = strlen(s1) - 1;
char s2[j+1];
strcpy(s2, s1);
while (j > -1)
{
s1[j--] = s2[i++];
}
}
10.第10题
#include
#include
#define SIZE 10
void sc(char * s1);
int main(void)
{
char s1[SIZE];
char * find;
printf("请输入s1:");
while (fgets(s1, SIZE, stdin) != NULL)
{
if (find = strchr(s1, '\n'))
*find = '\0';
else
while (getchar() != '\n');
sc(s1);
puts(s1);
printf("请输入s1:");
}
return 0;
}
void sc(char * s1)
{
int i, ii;
int j = strlen(s1);
for (i = 0; i < j; i++)
{
if (s1[i] == ' ')
{
for (ii = i; ii < j; ii++)
s1[ii] = s1[ii+1];
i--;
j--;
}
}
}
11.第11题
#include
#include
#define SIZE 100
#define NUM 10
char * s_gets(char *st, int n);
void s1(char *st [], int num);
void s2(char *st [], int num);
void s3(char *st [], int num);
void s4(char *st [], int num);
int menu(void);
int main(void)
{
char st[NUM][SIZE];
char *sts[NUM];
int ch;
int num = 0;
while (num < NUM)
{
printf("输入第%d字符串:",num+1);
if (s_gets(st[num], SIZE) == NULL)
break;
sts[num] = st[num];
num++;
}
putchar('\n');
while ((ch = menu()) != 5)
{
switch (ch)
{
case 1: s1(sts, num);
break;
case 2: s2(sts, num);
s1(sts, num);
break;
case 3: s3(sts, num);
s1(sts, num);
break;
case 4: s4(sts, num);
break;
}
}
return 0;
}
char * s_gets(char *st, int n)
{
char * ret_val;
char * find;
ret_val = fgets(st, n, stdin);
if (ret_val)
{
if (find = strchr(st, '\n'))
*find = '\n';
else
while (getchar() != '\n');
}
return ret_val;
}
int menu(void)
{
int ch;
puts("|=========================|");
puts("|1) 打印源字符串列表 |");
puts("|2) 以码表的顺序打印 |");
puts("|3) 按长度递增顺序打印 |");
puts("|4) 第一个单词的长度打印 |");
puts("|5) 退出 |");
puts("|=========================|");
puts("请输入<1-5>:");
while (scanf("%d",&ch) != 1 || ch > 5 || ch < 1)
{
while (getchar() != '\n');
puts("请输入<1-5>:");
}
return ch;
}
void s1(char *st[NUM], int num)
{
int i;
for (i = 0; i < num; i++)
puts(st[i]);
putchar('\n');
}
void s1(char *st[NUM], int num)
{
int i;
for (i = 0; i < num; i++)
puts(st[i]);
putchar('\n');
}
void s2(char *st [], int num)
{
int i,j;
char *temp;
for (i = 0; i < num - 1; i++)
for (j = i + 1; j < num; j++)
if (strcmp(st[i], st[j]) > 0)
{
temp = st[i];
st[i] = st[j];
st[j] = temp;
}
}
void s3(char *st [], int num)
{
int i, j;
char *temp;
for (i = 0; i < num - 1; i++)
for (j = i + 1; j < num; j++)
if (strlen(st[i]) > strlen(st[j]))
{
temp = st[i];
st[i] = st[j];
st[j] = temp;
}
}
void s4(char *st [], int num)
{
int i, j, k;
int sum;
char *temp;
for (i = 0; i < num; i++)
{
j = 0;
sum = 0;
while (st[i][j])
{
if (st[i][j] == ' ' || st[i][j] == ' ')
j++;
else
break;
}
while (st[i][j])
{
if (st[i][j] == ' ' || st[i][j] == ' ')
break;
else
{
j++;
sum++;
}
}
for (k = 0; k < sum; k++)
putchar(st[i][k]);
putchar('\n');
}
}
12.第12题
#include
#include
int main(void)
{
int ch;
int words = 0;
int word = 0;
int up = 0;
int lo = 0;
int pu = 0;
int num = 0;
while ((ch = getchar()) != EOF)
{
if (!isspace(ch) && !words)
{
words = 1;
word++;
}
if (isupper(ch))
up++;
if (islower(ch))
lo++;
if (ispunct(ch))
pu++;
if (isdigit(ch))
num++;
if (isspace(ch) && words)
words = 0;
}
printf("word = %d, up = %d\n", word, up);
printf("lo = %d, pu = %d\n", lo, pu);
printf("num = %d\n", num);
return 0;
}
13.第13题
#include
int main(int argc, char *argv [])
{
int i, j;
for (j = argc - 1, i = 1; i < argc; i++, j--)
{
printf("%s\n", argv[j]);
}
return 0;
}
14.第14题
#include
#include
int main(int argc, char *argv [])
{
double d;
double i;
double ds;
int j,k;
if (argc != 3)
puts("输入错误");
else
{
d = atof(argv[1]);
i = atof(argv[2]);
k = atoi(argv[2]);
ds = 1;
for (j = 1; j <= k; j++)
{
ds = ds * d;
}
printf("%.2lf的%d次幂为:%.2lf\n", d, k, ds);
}
return 0;
}
15.第15题
#include
#include
#include
#define SIZE 100
int atois(char *s1);
int main(void)
{
char st[SIZE];
char * find;
while (fgets(st, SIZE, stdin) != NULL)
{
if (find = strchr(st, '\n'))
*find = '\0';
else
while (getchar() != '\n');
printf("%d\n",atois(st));
}
return 0;
}
int atois(char *s1)
{
int len;
int num;
int i, j, k;
len = strlen(s1);
for (i = 0; i < len; i++)
if (!isdigit(s1[i]))
return 0;
for (k = len - 1, i = 0, j = 1, num = 0; i < len; i++, k--)
{
num += (s1[k] - '0') * j;
j *= 10;
}
return num;
}
16.第16题
#include
#include
#define SIZE 100
int main(int argc, char *argv [])
{
char st[SIZE];
char *find;
int i = 0;
while (fgets(st, SIZE, stdin) != NULL)
{
if (find = strchr(st, '\n'))
*find = '\0';
else
while (getchar() != '\n');
}
if (argc != 2 || strcmp(argv[1], "-p") == 0)
puts(st);
else if (strcmp(argv[1], "-u") == 0)
{
while (st[i])
{
if (islower(st[i]))
st[i] -= 32;
i++;
}
puts(st);
}
else if (strcmp(argv[1], "-l") == 0)
{
while (st[i])
{
if (isupper(st[i]))
st[i] += 32;
i++;
}
puts(st);
}
return 0;
}
