Question

自学C语言，计算输入值的阶乘，可是运算结果总是不对， 求教大大

#include <stdio.h>
#include <stdlib.h>
int main()
{
int a,b,j,n,t;
a=1;
b=1;
printf("input : ");
scanf("%d",&n);
while (b+1<=n)
{
j=a*b;

t=j;
a=t;

b=b+1;
}
printf("的阶乘是%d",j);

system("pause");
return 0;
}
目前只学到if...else 和while- -

Answer 1

#include <stdio.h>

int main()
{
int num,result;
scanf("%d",&num);
result=1;
if(num<0) printf("输入数据错误\n");
else if(num==0) printf("num的阶乘=%d\n",result);//0的阶乘等于1
else
{
while(num!=0)
{
result=result*num;
num=num-1;
}
printf("num的阶乘=%d\n",result);
}
return 0;
}
因为阶乘数字增大太快，所以这种算法局限性很大，只能算到13左右

//补充:任意数阶乘
#include <stdio.h>
int main()
{
int n,i,j,len,a[50000];
while(scanf("%d",&n)!=EOF)
{
memset(a,0,sizeof(a));
if(n<0) break;
if(n==0)
{
cout<<1<<endl;
continue;
}
for(i=len=a[0]=1;i<=n;i++)
{
for(j=0;j<len;j++)
a[j]*=i;
for(j=0;j<len-1;j++)
{
a[j+1]+=a[j]/10;
a[j]%=10;
}
while(a[len-1]>=10)
{
a[len]+=a[len-1]/10;
a[len-1]%=10;
len++;
}
}
for(i=len-1;i>=0;i--)
printf("%d",a[i]);
printf("\n");

}
return 0;
}

Answer 2

*= 这样的运算符学了吗？？

中间改成
j=1;a=1;
while(a<=n)
{
j*=a;
a++;

}

Answer 3

#include <stdio.h>
#include <stdlib.h>
int main()
{
int b,j,n;
j=1;
b=1;
printf("input : ");
scanf("%d",&n);
while (b<=n)
{
j=j*b;
b=b+1;
}
printf("的阶乘是%d",j);
system("pause");
return 0;
}