山东大学（威海）2022级大一下C习题集（1）

• 1-7-1 求幂级数展开的部分和
• 1-7-2 查询水果价格
• 1-7-3 猜数字游戏
• 1-7-4 特殊a串数列求和
• 1-7-5 成绩统计分析表
• 1-7-6 换硬币
• 1-7-7 验证“哥德巴赫猜想”

1-7-1 求幂级数展开的部分和

#include<stdio.h>
#include<math.h>
int main()
{
    double x = 0;
    scanf("%lf",&x);
    double add = 1.0,sum = 1.0;
    int i = 1;
    for(i = 1;;i++)
    {
        add=(add*x)/i;
        sum+=add;
        if(add<0.00001)
      		 break;
    }
    printf("%.4lf",sum);
    return 0;
}

1-7-2 查询水果价格

#include<stdio.h>
void menu()
{
    printf("[1] apple\n[2] pear\n[3] orange\n[4] grape\n[0] exit\n");
}

int main()
{
    menu();
    int c = 0, n;
    while(++c<6)
    {
        scanf("%d",&n);
        if(n == 0)
            break;
        
        switch(n)
        {
            case 1:printf("price = 3.00\n");
                    break;
            case 2:printf("price = 2.50\n");
                    break;
            case 3:printf("price = 4.10\n");
                    break;
            case 4:printf("price = 10.20\n");
                    break;
            default:printf("price = 0.00\n");
                    break;
        }
    }
    return 0;
}

1-7-3 猜数字游戏

#include<stdio.h>
int main()
{
   int rad1, N;
   scanf("%d%d", &rad1, &N);
    int gs = 0;
   if(rad1>0&&rad1<=100&&N>3)
    {
         
         for(int i = 0;i<N;i++)
         {
             scanf("%d", &gs);
             if (gs <= 0)
             {
                   printf("Game Over");
                   return 0;
             }
        else if (gs < rad1)
                printf("Too small\n");
        else if(gs>rad1)
                printf("Too big\n");
        else if(gs==rad1&&i == 0)
            {
                printf("Bingo!\n");
                return 0;
            }
            else if(gs == rad1&&(i == 1||i==2))
            {
                printf("Lucky You!\n");
                 return 0;
            }
            else if(gs == rad1)
            {
                printf("Good Guess!\n");
                 return 0;
            }
        }

            printf("Game Over\n");
            return 0;
      }
    
}

1-7-4 特殊a串数列求和

#include<stdio.h>
int main()
{
    int a,n;
    scanf("%d%d",&a,&n);
    int s = 0,sum = 0;
    for(int i = 1;i<=n;i++)
    {
        s = s*10+a;
        sum += s;
    }
    printf("s = %d",sum);
}

1-7-5 成绩统计分析表

#include<stdio.h>

void Print_s(double i)//把打印*封装成一个函数，方便
{
     int n = (int)floor(i+0.5);//四舍五入
     for(int j = 0;j<n;j++)
        printf("*");
}

int main()
{
    int n;
    scanf("%d", &n);
    double arr[1000] = { 0.0 };
    double sum = 0.0,max = 0.0,min = 1000.0,avg;
    int a=0,b=0,c=0,d=0,e=0;
    for (int i = 0; i < n; i++)
    {
        scanf("%lf", &arr[i]);
        sum += arr[i];
        if(arr[i]>max)
            max = arr[i];
        if(arr[i]<min)
            min = arr[i];
        
        if(arr[i]>=90&&arr[i]<=100)
            a++;
        else if(arr[i]>=80&&arr[i]<90)
            b++;
        else if(arr[i]>=70&&arr[i]<80)
            c++;
        else if(arr[i]>=60&&arr[i]<70)
            d++;
        else if(arr[i]>=0&&arr[i]<60)
            e++;
    }
    for (int i = 0; i < n; i++)
    {
        printf("%03d:%6.1lf ", i+1, arr[i]);
        Print_s(arr[i]);
        printf("\n");
    }
    avg = sum / n;
    printf("\nMax: %5.1lf ",max);
        Print_s(max);
        printf("\nMin: %5.1lf ",min);
        Print_s(min);
        printf("\nAvg: %5.1lf ",avg);
        Print_s(avg);
        printf("\n");
    
    double A = 100.0*a/n,B=100.0*b/n,C = 100.0*c/n,D = 100.0*d/n,E = 100.0*e/n;
    
    //printf里打印一个百分号“%”要写两个：%%
    printf("\nA:%6.1lf%%",A);
    printf(" ");
    Print_s(A);
    printf("\nB:%6.1lf%%",B);
    printf(" ");
    Print_s(B);
    printf("\nC:%6.1lf%%",C);
    printf(" ");
    Print_s(C);
    printf("\nD:%6.1lf%%",D);
    printf(" ");
    Print_s(D);
    printf("\nE:%6.1lf%%",E);
    printf(" ");
    Print_s(E);
    return 0;
}

1-7-6 换硬币

#include<stdio.h>
int main()
{
    int x = 0;
    scanf("%d", &x);
    int f5 = 0, f2 = 0, f1 = 0;
    int count = 0;
    for (int i = x/5;; i--)
    {
        f5 = i;
        for (int j = (x-5*f5)/2;; j--)
        {
            f2 = j;
            f1 = x - 5 * f5 - 2 * f2;
            if (f2 == 0)
            { 
                break;
            }
            if (f1 <= 0)
            {  
                continue;
            }
            printf("fen5:%d, fen2:%d, fen1:%d, total:%d\n", f5, f2, f1, f1 + f2 + f5);
            count++;
        }
        if ((f5 == 1))
        {
            printf("count = %d\n", count);
            break;
        }
    }
    return 0;
}

1-7-7 验证“哥德巴赫猜想”

#include<stdio.h>
#include<math.h>
int Prime(long long i)
{
    int c = 0;
    for(long long int j = 2;j<=sqrt(i);j++)
    {
        if(i%j==0)
            return 0;
    }
    return 1;
}

int main()
{
    long long int n;
    scanf("%lld",&n);
    for(long long int i = 2;i<n;i++)
    {
        if(Prime(i)&&Prime(n-i))
        {
            printf("%lld = %lld + %lld",n,i,n-i);
            break;
        }
        else 
            continue;
    }
    return 0;
}