void main()
{
int a,i=0,sum=0
scanf("%d",&a)
while(a)
{
a/=10
i++//i为位数
}
printf("%d位数,各位数字之和为%d\n",i,sum)
}
这是求n个数的全排列：#include <stdio.h>
int s[21] = {0}
int n = 0
void swap(int a, int b)
{
int t
t = s[a]
s[a] = s[b]
s[b] = t
}
void fp(int m)
{
int i
if (m == n)
{
for (i = 0i <n++i)
{
printf("%d", s[i])
}
printf("\n")
return
}
for (i = mi <n++i)
{
swap(m, i)
fp(m + 1)
swap(i, m)
}
}
int main(void)
{
scanf("%d", &n)
for (int i = 0i <n++i)
{
s[i] = i + 1
}
fp(0)
return 0
}
//C语言求一个三位数的各位数和#include <stdio.h>
int main(void)
{
int Num=0
scanf("%d",&Num)
printf("百位：%d\n",Num/100)
printf("十位：%d\n",Num/10%10)
printf("各位：%d\n",Num%10)
puts("")
int Sum=Num/100+Num/10%10+Num%10
printf("%d+%d+%d=%d\n",Num/100,Num/10%10,Num%10,Sum)
puts("")
return 0
}
