C语言:循环作业参考程序

Code
/*判定一个数是否为素数 */
int IsPrime(unsigned long n)
{
int i;
if(n==1 || n==0)
return 0;
for(i=2; i<=sqrt(n); i++)
if(n%i == 0)
return 0;

return 1;
}

/*三位素数的个数 */
int SanWeiSuShu()
{
int i;
int Sum = 0;
for(i=100; i<10000; i++)
{
if(IsPrime(i))
Sum++;
}
return Sum;
}

/*整数倒置 */
long Reverse(long n)
{
long i = 0;
while(n)
{
i = i * 10 + n % 10;
n /= 10;
}
return i;
}

/*判断回文数 */
int Palindrome(long n)
{
return (n == Reverse(n));
}

/*数制转换 */
long DToO(long n)
{/* 十进制 到八进制的转换 */
long i=0;
while(n)
{
i =i * 10 + n % 8;
n /= 8;
}
return Reverse(i);
}

/*质因数分解 */
void Despose(unsigned long n)
{
unsigned long int i;
for(i=2; i<=n; i++)
{
while(n!=1)
{
if(n % i == 0)
{
printf("%5ld", i);
n /= i;
}
else
break;
}
}
}

/*统计字符串中, 英文字母、空格、数字和其它字符的个数*/
void Count(char *s)
{
char *p = s;
int letter = 0;
int space = 0;
int number = 0;
int other = 0;

while(*p != '\0')
{
if( (*p >= 'a' && *p <= 'z')
||(*p >= 'A' && *p <= 'Z') )
letter++;
else if( *p == ' ')
space++;
else if(*p >= '0' && *p <= '9')
number++;
else
other++;
p++;
}
printf("the counts are:\nletter: %d, \nspace: %d, \nnumber: %d, \nother charater: %d.\n",
letter, space, number, other);
}