实验3 C语言函数应用编程

实验1

#include <stdio.h>
char score_to_grade(int score); 
int main() {
    int score;
    char grade;

    while(scanf("%d", &score) != EOF) {
        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;
}

 

功能：将分数转化为等级

形参类型：int

返回值类型：字符串

修改后 不会退出程序 会继续运行下面的 并且字符串外应该用''单引号

 

 

实验2

#include <stdio.h>
int sum_digits(int n); 
int main() {
    int n;
    int ans;

    while(printf("Enter n: "), scanf("%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;
}

 

功能：计算n的各数字之和

能 第一种是循环迭代 第二种是递归

 

实验3

#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;
    }
}

 功能：计算x的n次方

 

实验4

#include <stdio.h>
int is_prime(int n) {
    int i;
    if (n <= 1) return 0;
    if (n == 2) return 1;
    if (n % 2 == 0) return 0;
    
    for (i = 3; i * i <= n; i += 2) {
        if (n % i == 0) return 0;
    }
    return 1;
}

int main() {
    int n;
    int count = 0;
    
    printf("100以内的孪生素数：\n");
    for (n = 2; n <= 98; n++) {
        if (is_prime(n) && is_prime(n + 2)) {
            printf("%d %d\n", n, n + 2);
            count++;
        }
    }
    
    printf("\n100以内的孪生素数共有%d个\n", count);
    
    return 0;
}

 

实验5

#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 - 1, m) + func(n - 1, m - 1);  
}

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

 

实验6

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

int main() {
    int a, b, c;
    int ans;

    while(scanf("%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 (b < min) min = b;
    if (c < min) min = c;
    int i;
    for (i = min; i >= 1; i--) {
        if (a % i == 0 && b % i == 0 && c % i == 0) {
            return i;  
        }
    }
    
    return 1;  
}

 

实验7

#include <stdio.h>
#include <stdlib.h>
void print_charman(int n);

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

void print_charman(int n) {
    int i;
    for (i = 0; i < n; i++) {
        printf(" O    ");
    }
    printf("\n");
    for (i = 0; i < n; i++) {
        printf("<h>   ");
    }
    printf("\n");
    for (i = 0; i < n; i++) {
        printf("I I   ");
    }
    printf("\n");
}