实验三

task1

代码
`#include <stdio.h>

char score_to_grade(int score);

int main() {
int score;
char grade;

while (scanf_s("%d", &score)) {
grade = score_to_grade(score);
printf("分数: %d, 等级: %c\n\n", score, grade);
}

return 0;
}

char score_to_grade(int score) {
char ans;

switch (score / 10) {
case 10:
case 9: ans = 'A'; break;
case 8: ans = 'B'; break;
case 7: ans = 'C'; break;
case 6: ans = 'D'; break;
default: ans = 'E';
}

return ans;
}
`
运行结果截图

问题
1.将分数划等级；
形参类型为int，返回值类型为char
2.改为双引号后变量ans无法获取值
评分始终为E

task2

代码
`#include <stdio.h>

int sum_digits(int n);

int main() {
int n;
int ans;

while (printf("Enter n: "), scanf_s("%d", &n) != EOF) {
ans = sum_digits(n);
printf("n = %d, ans = %d\n\n", n, ans);
}

return 0;
}

int sum_digits(int n) {
int ans = 0;

while (n != 0) {
ans += n % 10;
n /= 10;
}

return ans;
}
`
运行结果截图

问题
1.计算一个整数的所有位数上的数字之和
2.可以，第一种是迭代方式，第二种是递归方式

task3

代码
`#define _CRT_SECURE_NO_WARNINGS

include<stdio.h>

int power(int x, int n);

int main() {
int x, n;
int ans;

while (printf("Enter x and n: "), scanf("%d%d", &x, &n) != EOF) {
ans = power(x, n);
printf("n = %d, ans = %d\n\n", n, ans);
}

return 0;
}

int power(int x, int n) {
int t;

if (n == 0)
return 1;
else if (n % 2)
return x * power(x, n - 1);
else {
t = power(x, n / 2);
return t * t;
}
}`
运行结果截图

问题
1.计算x的n次方
2.是

task4

代码`#define _CRT_SECURE_NO_WARNINGS

include<stdio.h>

int classify_triangle(int, int, int);

int main() {
int a, b, c;
while (scanf("%d%d%d", &a, &b, &c) != EOF) {
switch (classify_triangle(a, b, c)) {
case 0:printf("不能构成三角形\n\n"); break;
case 1:printf("普通三角形\n\n"); break;
case 2:printf("等边三角形\n\n"); break;
case 3:printf("等腰三角形\n\n"); break;
case 4:printf("直角三角形\n\n"); break;
default:;
}
}
}

int classify_triangle(int a, int b, int c) {
if (!(a + b > c && a + c > b && b + c > a))
return 0;
if (a == b && a == c && b == c)
return 2;
else if (a == b || a == c || b == c)
return 3;
else if (a * a + b * b == c * c || a * a + c * c == b * b || b * b + c * c == a * a)
return 4;
else
return 1;
}`
运行结果截图

task5

迭代法
`#include <stdio.h>
int func(int n, int m);
int main() {
int n, m;
int ans;
while (scanf_s("%d %d", &n, &m)!= EOF) {
ans = func(n, m);
printf("n = %d,m = %d,ans = %d\n\n", n, m, ans);
}
return 0;
}

int func(int n, int m) {
int ans=1;
int i=m;
if (n < m) {
ans = 0;
}
else if(m==0) {
ans = 1;
}
else {
while (i>0) {
ans = ans*n;
n--;
i--;
}
while (m > 0) {
ans = ans / m;
m--;
}
}
return ans;

}
`
运行结果截图

递归法
`#include <stdio.h>
int func(int n, int m);
int main() {
int n, m;
int ans;
while (scanf_s("%d %d", &n, &m)!= EOF) {
ans = func(n, m);
printf("n = %d,m = %d,ans = %d\n\n", n, m, ans);
}
return 0;
}

int func(int n, int m) {
int ans=1;
if (n < m) {
return 0;
}
else if (n == m || m == 0) {
return 1;
}
else if (m == 1) {
return n;
}
else {
return func(n - 1, m) + func(n - 1, m - 1);
ans = n / m;
}
return ans;
}
`
运行结果截图

task6

#include<stdio.h> int gcd(int a, int b, int c); int main() { int a, b, c; int ans; while (scanf_s("%d%d%d", &a, &b, &c) != EOF) { ans = gcd(a, b, c); printf("最大公约数： %d\n\n", ans); } return 0; } int gcd(int a, int b, int c) { int min=a; if (min > b) { min = b; } else if(min>c){ min = c; } while (min != 0) { if (a % min == 0 && b % min == 0 && c % min == 0) { return min; } min--; } }
运行结果截图

task7

`#define _CRT_SECURE_NO_WARNINGS

include<stdio.h>

void print_charman(int);

int main() {
int n;
printf("Enter n: ");
scanf("%d", &n);
print_charman(n);

return 0;
}

void print_charman(int n) {
int i, j, k = n;
for (i = 0; i < n; ++i) {
for (j = 0; j < i; ++j) {
printf("\t");
}
for (j = 0; j < 2 * k - 1; ++j) {
printf(" 0 \t");
}
printf("\n");
for (j = 0; j < i; ++j) {
printf("\t");
}
for (j = 0; j < 2 * k - 1; ++j) {
printf("\t");
}
printf("\n");
for (j = 0; j < i; ++j) {
printf("\t");
}
for (j = 0; j < 2 * k - 1; ++j) {
printf("I I\t");
}
printf("\n");
k--;
}
}`
运行结果截图