20131007国庆作业例7-11,7-12，7-13,7-14

#include<stdio.h>
int main(void)
{
int i,n,m;
char s[10];

printf("Enter a string:");
i=0;
while((s[i]=getchar())!='\n')
i++;
s[i]='\0';

for(n=0,m=i-1;n<m;n++,m--)
if(s
!=s[m])
break;
if(n>=m)
printf("It is a plalindrome\n");
else
printf("It is not a plalindrome\n");

return 0;
}

#include<stdio.h>
int main(void)
{
int i,number;
char str[10];

printf("Enter a string:");
i=0;
while((str[i]=getchar())!='\n')
i++;
str[i]='\0';

number=0;
for(i=0;str[i]!='\0';i++)
if(str[i]>='0'&& str[i]<='9')
number=number*10+str[i]-'0';

printf("digit=%d\n",number);

return 0;
}

#include<stdio.h>
int main(void)
{
int count,i;
char str[80];

printf("Enter a string:");
i=0;
while((str[i]=getchar())!='\n')
i++;
str[i]='\0';

count=0;
for(i=0;str[i]!='\0';i++)
if(str[i]<='9'&&str[i]>='0')
count++;
printf("count=%d\n",count);

return 0;
}

#include<stdio.h>
int main(void)
{
int i,k;
char str1[80],str2[80];
long number;
printf("Enter a string:");
i=0;
while((str1[i]=getchar())!='\n')
i++;
str1[i]='\0';

k=0;
for(i=0;str1[i]!='\0';i++)
if
(str1[i]>='0'&&str1[i]<='9'||str1[i]>='a'&&str1[i]<='f'||str1[i]>='A'&&str1[i]<='F')
{
str2[k]=str1[i];
k++;
}
str2[k]='\0';

number=0;
for(i=0;str2[i]!='\0';i++)
if(str2[i]>='0'&&str2[i]<='9')
number=number*16+str2[i]-'0';
else if(str2[i]>='a'&&str2[i]<='f')
number=number*16+str2[i]-'a'+10;
else if(str2[i]>='A'&&str2[i]<='F')
number=number*16+str2[i]-'A'+10;
printf("New string:");
for(i=0;str2[i]!='\0';i++)
putchar(str2[i]);
printf("\n");
printf("number=%1d\n",number);

return 0;
}