关于for的使用!!
1、输入一行字符,统计并输出其中的英文字母、数字字符和其他字符的个数!!2、s=1!+(1!+2!)+(1!+2!+3!)+…+(1!+2!+3!…n!) n有键盘输入
程序代码:#include < stdio.h >
#include < stdlib.h >
#include < ctype.h >
void main ( )
{
char ch;
int sum1 = 0;
int sum2 = 0;
int sum3 = 0;
int sum4 = 0;
while((ch=getchar())!='\n')
{
if ( isdigit ( ch ) != 0 )
sum1++;
else if ( isspace ( ch ) != 0 )
sum2++;
else if ( islower ( ch ) != 0 || isupper ( ch ) != 0 )
sum3++;
else
sum4++;
}
printf ( "%5d%5d%5d%5d", sum1, sum2, sum3, sum4 );
system ( "pause" );
}
下题晚上来,上自习去了

程序代码:#include <stdio.h>
long long fac(long long );
int main(void)
{
long long n, s, i;
printf("Enter n: \n");
scanf("%lld",&n);
for (i = 1, s = 0; i <= n; i++)
{
s = s + fac(i) * (n - i + 1);
}
printf("result = %lld\n",s);
return 0;
}
long long fac(long long i)
{
long long int f;
if (i == 0 || i == 1)
{
f = 1;
}
else
{
f = fac(i - 1) * i;
}
return f;
}
程序代码:#include < stdio.h >
void main ( )
{
char c;
int letters=0,space=0,numbers=0,others=0;
printf("please input some characters\n");
while((c=getchar())!='\n')
{
if(c>='a'&&c<='z'||c>='A'&&c<='Z')
letters++;
else if(c==' ')
space++;
else if(c>='0'&&c<='9')
numbers++;
else
others++;
}
printf("All characters: \nchar=%d\nspace=%d\nnubers=%d\nothers=%d\n",letters,space,numbers,others);
}