实验三

#include <stdio.h>
char score_to_grade(int score);  // 函数声明
int main() {
    int score;
    char grade;
    while(scanf("%d", &score) != EOF) {
        grade = score_to_grade(score);  // 函数调用
        printf("分数: %d, 等级: %c\n\n", score, grade);
    }
    return 0;
}
// 函数定义
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;
}

 任务二

#include <stdio.h>
int sum_digits(int n);  // 函数声明
int main() {
    int n;
    int ans;
    while(printf("Enter n: "), scanf("%d", &n) != EOF) {
        ans = sum_digits(n);    // 函数调用
        printf("n = %d, ans = %d\n\n", n, ans);
    }
    return 0;
}
// 函数定义
int sum_digits(int n) {
    int ans = 0;
    while(n != 0) {
        ans += n % 10;
        n /= 10;
    }
    return ans;
}

 任务三

 1 #include <stdio.h>
 2 int power(int x, int n);
 3 int main() {
 4     int x, n;
 5     int ans;
 6     while(printf("Enter x and n: "), scanf("%d%d", &x, &n) != EOF) {
 7         ans = power(x, n);
 8         printf("n = %d, ans = %d\n\n", n, ans);
 9     }
10     return 0;
11 }
12 
13 int power(int x, int n) {
14     int t;
15     if(n == 0)
16         return 1;
17     else if(n % 2)
18         return x * power(x, n-1);
19     else {
20         t = power(x, n/2);
21         return t*t;
22     }
23 }

 任务四

#include <stdio.h>
int classify_triangle(int a, int b, int c);

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

int classify_triangle(int a, int b, int c) {
    if(a + b <= c || a + c <= b || b + c <= a)
        return 0;
    if(a == b && b == c)
        return 2;
    if(a*a + b*b == c*c || a*a + c*c == b*b || b*b + c*c == a*a)
        return 4;
    if(a == b || a == c || b == c)
        return 3;
    return 1;
}

 任务五

#include <stdio.h>
int func(int n, int m);

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

    while(scanf("%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) {
    if (m < 0 || m > n) return 0; 
    if (m == 0 || m == n) return 1;
    if (m > n - m) m = n - m;

    int result = 1;
    for (int i = 1; i <= m; i++) {
        result = result * (n - m + i) / i;
    }
    return result;

#include <stdio.h>
int func(int n, int m);

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

    while(scanf("%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) {
    if (m < 0 || m > n) return 0;
    if (m == 0 || m == n) return 1;
    return func(n - 

 任务六

#include <stdio.h>
int gcd(int a, int b, int c);

int main() {
    int a, b, c;
    while(scanf("%d%d%d", &a, &b, &c) != EOF) {
        int ans = gcd(a, b, c);
        printf("最大公约数: %d\n", ans);
    }
    return 0;
}

int gcd(int a, int b, int c) {
    int min = a < b ? a : b;
    min = min < c ? min : c;
    for(int i = min; i >= 1; --i) {
        if(a%i == 0 && b%i == 0 && c%i == 0)
            return i;
    }
    return 1;
}

 

#include <stdio.h>

void print_charman(int n);

int main() {
    int n;
    printf("Enter n: ");
    scanf("%d", &n);
    print_charman(n);
    return 0;
}

void print_charman(int n) {
    for(int k = n; k >= 1; k--) {
        for(int i = 0; i < k; i++)
            printf("0    ");
        printf("\n");

        for(int i = 0; i < k; i++)
            printf("<H>  ");
        printf("\n");

        for(int i = 0; i < k; i++)
            printf("I I  ");
        printf("\n");
    }
}