实验一：
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <windows.h>
#define N 80
void print_text(int line, int col, char text[]);
void print_spaces(int n);
void print_blank_lines(int n);
int main() {
int line, col, i;
char text[N] = "hi, April~";
srand(time(0));
for(i = 1; i <= 10; ++i) {
line = rand() % 25;
col = rand() % 80;
print_text(line, col, text);
Sleep(1000);
}
return 0;
}
void print_spaces(int n) {
int i;
for(i = 1; i <= n; ++i)
printf(" ");
}
void print_blank_lines(int n) {
int i;
for(i = 1; i <= n; ++i)
printf("\n");
}
void print_text(int line, int col, char text[]) {
print_blank_lines(line-1);
print_spaces(col-1);
printf("%s", text);
}
问题回答：该代码旨在分别随机地从1~25，1~80中取两个数作为line与col，随后打印line-1个空行后打印col-1个空格，再打印相应文本。随后程序暂停1000毫秒后继续进行。
实验二：
task2_1.c
#include <stdio.h>
long long fac(int n);
int main() {
int i, n;
printf("Enter n: ");
scanf("%d", &n);
for (i = 1; i <= n; ++i)
printf("%d! = %lld\n", i, fac(i));
return 0;
}
long long fac(int n) {
static long long p = 1;
printf("p = %lld\n", p);
p = p * n;
return p;
}
实验图片：
task2_2.c
#include <stdio.h>
int func(int, int);
int main() {
int k = 4, m = 1, p1, p2;
p1 = func(k, m);
p2 = func(k, m);
printf("%d, %d\n", p1, p2);
return 0;
}
int func(int a, int b) {
static int m = 0, i = 2;
i += m + 1;
m = i + a + b;
return m;
}
实验图片：
问题回答：static所修饰的变量在被赋初值后会持续保留在作用域中，直到变量改变或程序结束。
实验三：
#include <stdio.h>
long long func(int n);
int main() {
int n;
long long f;
while (scanf("%d", &n) != EOF) {
f = func(n);
printf("n = %d, f = %lld\n", n, f);
}
return 0;
}
long long func(int n)
{
if(n == 1)
return 1;
else
return func(n-1) * 2 + 1;
}
实验图片：
实验四：
#include <stdio.h>
int func(int n, int m);
int main() {
int n, m;
while(scanf("%d%d", &n, &m) != EOF)
printf("n = %d, m = %d, ans = %d\n", n, m, func(n, m));
return 0;
}
int func(int n, int m)
{
if(n > m && m != 0)
return func(n - 1, m) + func(n - 1, m - 1);
else if(n < m)
return 0;
else if(m == 0 || n == m)
return 1;
}
实验图片：
实验五：
迭代法：
#include <stdio.h>
double mypow(int x, int y);
int main() {
int x, y;
double ans;
while(scanf("%d%d", &x, &y) != EOF) {
ans = mypow(x, y);
printf("%d的%d次方: %g\n\n", x, y, ans);
}
return 0;
}
double mypow(int x, int y)
{
double i, X = x, sum = 1;
if(y > 0){
for(i = 1; i <= y; i++)
sum *= X;
return sum;}
else if(y < 0){
for(i = 1; i <= -y; i++)
sum *= 1 / X;
return sum;}
else if(y == 0)
return 1;
}
实验图片：
函数递归法：
#include <stdio.h>
double mypow(int x, int y);
int main() {
int x, y;
double ans;
while(scanf("%d%d", &x, &y) != EOF) {
ans = mypow(x, y);
printf("%d的%d次方: %g\n\n", x, y, ans);
}
return 0;
}
double mypow(int x, int y)
{
double X = x;
if(y > 0)
{
if(y == 1)
return x;
else if(y != 1)
return mypow(x, y - 1) * x;
}
else if(y < 0)
{
if(y == 1)
return 1 / X;
else if(y != 1)
return mypow(X, y + 1) * 1 / X;
}
else
return 1;
}
实验图片：
实验六：
#include<stdio.h>
#include<math.h>
void hanoi(unsigned int n, char from, char temp, char to);
void moveplate(unsigned int n, char from, char to);
static double total, delta;//total定义:从程序起总共移动次数；delta定义：最近上一次移动的移动次数
int main()
{
unsigned int n;
int num;//定义：本次移动次数
while(scanf("%d", &n) != EOF)
{
hanoi(n,'A','B','C');
printf("\n");
num = total - delta;
printf("一共移动了%d次\n", num);
delta = total;
printf("\n");
}
return 0;
}
void hanoi(unsigned int n, char from, char temp, char to)
{
if(n == 1){
moveplate(n, from, to);}
else
{
hanoi(n - 1, from, to, temp);
moveplate(n, from, to);
hanoi(n - 1, temp, from, to);
}
}
void moveplate(unsigned int n, char from, char to)
{
printf("%u : %c --> %c \n", n, from, to);total++;
}
实验图片：
实验七：
#include<stdio.h>
#include<math.h>
int is_prime(int x)
{
int i;
for(i = 2; i <= sqrt(x); i++)
if(x % i == 0)
return 0;
return 1;
}
void print(int x)
{
int i;
for(i = 2; i <= x / 2; i++)
{
if((is_prime(i) && is_prime(x - i)))
{
printf("%d = %d + %d\n", x, i, x - i);
return;
}
}
}
int main()
{
int i;
for(i = 2; i <= 20; i += 2)
print(i);
return 0;
}
实验图片：
实验八：
#include <stdio.h>
#include <math.h>
long func(long s);
int main() {
long s, t;
printf("Enter a number: ");
while (scanf("%ld", &s) != EOF) {
t = func(s);
printf("new number is: %ld\n\n", t);
printf("Enter a number: ");
}
return 0;
}
long func(long s)
{
long yushu, result = 0, j = 1, i;
for(i = 1; s != 0; i++)
{
yushu = s % 10;
if(yushu % 2 == 1)
{
result += yushu * j;
j *= 10;
}
s /= 10;
}
return result;
}
实验图片：