第1次C练习

#include<stdio.h>

#define N   3

int maxNum(int a, int b){
return (a > b ? a : b);
}

void main(void){
int num,i = 0;
int max = 0;
while(i++ < N){
printf("请输入第%d个整数：", i);
scanf("%d",&num);
max = maxNum(max,num);
}
printf("最大数为：%d。\n", max);
}

#include<stdio.h>

double add(int n);
double jiecheng(int n);

double jiecheng(int n){
double ans = 0;
double tmp = 1;
int i;
for(i = 1; i <= n; i++, tmp *= i)
ans += tmp;
return ans;
}

void main(void){
int n;

printf("你想求多少的阶乘之和");
scanf("%d", &n);
printf("最后的结果为：%.lf。\n", jiecheng(n));
}

#include<stdio.h>

int ars(int value){
int ars = 0;
unsign char f = 0;
if(value < 0)
f = 1；
while(value){
ars = ars*10+(value%10+6)%8;
value /= 10;
}
return f ? (-1 * ars) : ars;
}

void main(void){
int value;
printf("请输入一个五位整数：");
scanf("%d", &value);
printf("加密后的数字为%d。\n", ars(value));
}