C语言函数function练习题

#include <stdio.h>
#include <math.h>
#include <string.h>
#include <conio.h>

int main111(void)
{
    #if( 0 )
        void avg(void);
        avg();
    #endif    //去掉一个最高分和最低分求平均分

    #if( 0 )
        void calroot(double a, double b, double c);
        double x , y , z;
        printf("输入方程的系数a：");
        scanf("%lf",&x);
        printf("输入方程的系数b：");
        scanf("%lf",&y);
        printf("输入方程的系数c：");
        scanf("%lf",&z);
        calroot(x,y,z);
    #endif    //求一元二次方程的根

    #if( 0 )
        double sum(int n),result = 0;
        int x;
        printf("input a param\n");
        scanf("%d",&x);
        result = sum(x);
        printf("%.2lf",result);
    #endif    //求1-1/2+1/3-1/4+...+(-1)^(n+1)/n

    #if( 0 )
//辗转相除法
/*    
    int a,b,x,y;
    int t;
    scanf("%d %d", &a, &b);
    x = a , y = b;
    while (b !=0 ){
        t = a%b;
        a = b;
        b = t;
        printf("a=%d b=%d t=%d\n",a , b, t);
    }
    printf("最大公约数是%d\n", a);
    printf("最小公倍数%3d",x*y/a);*/        //最小公倍数=两数的乘积/最大公约（因）数

//更相减损法
/* 
    int n1, n2;
    
    printf("输入两个数，以空格分隔: ");
    scanf("%d %d",&n1,&n2);
 
    while(n1!=n2)
    {
        if(n1 > n2)
            n1 -= n2;
        else
            n2 -= n1;
    }
    printf("GCD = %d",n1);
 */



    int gcd(int a,int b);
    int result;
    result = gcd(319,377);
    printf("%d",result);
    #endif    //求形参m,n的最大公约数

    #if( 0 )
    ①
    *double x,y,i;
    int a,b;
    x = 3.0;
    do
    {
        i = 2.0;
        do
        {
            y =  x / i;
            a = (int)y;
            if( y != a)
            {
                if(i == x-a)
                {
                    b = (int)x;
                    printf("%d\n",b);
                }
            }
            i++;
        } while (y != a);
        x++;
    } while (x <= 100.0);*/
    ②
    int a=0, i;  // 素数的个数
    int num=0;  // 输入的整数
    printf("输入一个整数：");
    scanf("%d",&num);
    for( i=2;i<num;i++){
        if(num%i==0){
            a++;  // 素数个数加1
        }
    }
    if(a==0){
        printf("%d是素数。\n", num);
    }else{
        printf("%d不是素数。\n", num);
    }
    ③
    int k,i,tag;
    for(i=2;i<=100;i++)
    {
        tag=0;
        for(k=2;k<i;k++)
        {
            if(i%k==0)
                tag=1;
        }
        if(tag==0)
            printf("%d,",i);
    }
    ④
    *int m,i,k,h=0,leap=1;
     for(m=2;m<=100;m++){ 
         k=(int)sqrt((double)m+1);
         for(i=2;i<=k;i++)
             if(m%i==0){
                 leap=0;
                 break;
             }
         if(leap){
             printf("%d\n",m);
         }
         leap=1;
        */
      }
    #endif    //求质数

    #if( 0 )
    int k,num;long sum=0;
    scanf("%d",&num);
    for(k=1;k<=num;k++)
    sum=sum+h2(k);
    printf("(1!)+(1!+2!)+...+(1!+2!+...+%d!)=%ld\n",num,sum);
    #endif    //计算s=(1!)+(1!+2!)+...+(1!+2!...+n!)

    #if( 0 )
    int a[10],i, sushu(int x);
    for ( i = 0; i < 10; i++)
    {
        scanf("%d",&a[i]);
    }
    printf("sushu are ");
    for ( i = 0; i < 10; i++)
    {
        if(sushu(a[i]))    printf("%5d", a[i]);
    }
    #endif    //输出一个数组里面的质数

    #if( 0 )
    int a[10],i, sushu(int x);
    for ( i = 0; i < 10; i++)
    {
        scanf("%d",&a[i]);
    }
    printf("sushu are ");
    for ( i = 0; i < 10; i++)
    {
        if(sushu(a[i])) printf("%5d", a[i]);
    }
    #endif    //在一个一维数组中存放10个正整数，求其中所有的素数

    #if( 0 )
    void inverse(char str[]);
    char str[100];
    printf("input string");
    gets(str);
    inverse(str);
    puts(str);
    #endif    //反序输出一个输入的字符串
    
    #if( 0 )
    void space(char str[]);
    char  a[80];
    gets(a);
    space(a);
    puts(a);
    #endif    //输入一个数字字符 每两个数字间空一个空格   "1 9 9 0"

    #if( 0 )
    void sort(char(*s)[6]);
    char str[10][6];
    char(*p)[6];
    int i;
    printf("input 10 string");
    for ( i = 0; i < 10; i++)
    {
        scanf("%s",str[i]);
    }
    p = str;
    sort(p);
    printf("Now,the sequence is:\n");
    for ( i = 0; i < 10; i++)
    {
        printf("%s\n",str[i]);
    //}
    #endif    //编写一个程序，在主函数中输入10个!等长!的字符串。用另一个函数sort()对它们排序，要求形参是指向由6个元素组成的一维数组的行指针，然后在主函数输出这10个已排好的字符串。

    #if( 0 )
    int fun(int a);
    int i, sum = 0;
    for ( i = 1; i <= 100; i++)
    {
            sum += fun(i);
    }
    printf("和为%d , 平均值：%.2f",sum,sum/100.0);
    #endif    //1,1,2,3,5,8,13,...的前100项的和及平均值

    //int i,j,x;
    //for ( i = 0; i <=4 ; i++)
    //{
    //    for ( j = 1; j <= 4-i; j++)
    //        printf(" ");
    //    for ( j = 0; j <=2*i-1 ; j++)
    //        printf("*"); 
    //        printf("\n");
    //}
//int num[]={3,4,5,6,7,8,9,10,11,12,13,14};
//int i,j,k,x,y;
// x=0;y=12-1;
// while(x<=y)
// {j=num[x];i=2;k=1;
// while (i<=j/2&&k) // 判断 j 是否为素数
// k=j%i++;
// if (k)
// printf( "%3d" ,num[x++]);
// else //j 不是素数首尾数据互换，尾指针前移
// {num[x]=num[y];
// num[y--]=j;
// }
// }
 //for (i=0;i<12;i++)
 //printf( "%5d" ,num[i]);
    //int a[3][4] = {{2,3,4,6},{3,1,2,3},{0,1,2,3}} , b[4][5] = {{3,-1,1,3,1},{2,0,3,5,4},{1,2,2,3,0},{1,2,3,4,2}}, c[3][5] , i , j , k , s;
    //for ( i = 0; i < 3; i++)
    //{
    //    for ( j = 0; j < 5; j++)
    //    {
    //        for ( k = 0 ,s = 0; k <4; k++)
    //        {
    //            s += a[i][k] * b[k][j] ; 
    //        }
    //        c[i][j] = s;
    //    }
    //}
    //for ( i = 0; i < 3; i++)
    //{
    //    for ( j = 0; j < 5; j++)
    //    {
    //        printf("%3d",c[i][j]);
    //    }
    //    printf("\n");
    //}
    
    //int a[9]={11,23,41,27,42,64,82,59};
 //int i=0,x;
 //scanf("%d",&x);
 // a[8] = x ;
 //while(a[i]!=x) i++;
 //if( i < 8 ) printf("Found! The index is:%d\n",i);
 //else printf("Can't found!\n");
    #if(0)
    int score[40],n;
    int ReadScore(int score[]);
    void PrintScore(int score[],int n);
    void AscendingSort(int a[],int n);
    void DescendingSort(int a[],int n);
    int order;    /* 值为1表示升序排序，值为2表示降序排序*/
    n = ReadScore(score);
    printf("Total students are %d\n",n);
    printf("Enter 1 to sort in ascending order,\n");
    printf("Enter 2 to sort in descending order:");
    scanf("%d",&order);
    if(order == 1)
    {
        AscendingSort(score,n);    //按升序排序
        printf("Data items in ascending order\n");
    }
    else
    {
        DescendingSort(score,n); //按降序排序
        printf("Data items in descending order\n");
    }
    PrintScore(score,n);
    #endif //函数实现升序降序

    #if(0)
    int score[40],n;
    int ReadScore1(int score[]);
    void PrintScore1(int score[],int n);
    void SelectingSort(int a[], int n, int (*compare)(int a,int b));
    int AscendingSort1(int a,int b);
    int DescendingSort1(int a,int b);
    int order;    /* 值为1表示升序排序，值为2表示降序排序*/
    n = ReadScore(score);
    printf("Total students are %d\n",n);
    printf("Enter 1 to sort in ascending order,\n");
    printf("Enter 2 to sort in descending order:");
    scanf("%d",&order);
    if(order == 1)
    {
        SelectingSort(score,n,AscendingSort1);    //按升序排序
        printf("Data items in ascending order\n");
    }
    else
    {
        SelectingSort(score,n,DescendingSort1); //按降序排序
        printf("Data items in descending order\n");
    }
    PrintScore1(score,n);
    #endif //指针函数实现升序降序

    /*char *w[] = {"Monday","Tuesday","Wednesday","Thursday","Friday","Saturday","Sunday"};
    char *st;
    int i , j ,k;
    printf("排序前\n");
    for ( i = 0; i < 7; i++)
    {
        printf("%p\t%s\n",w[i],w[i]);
    }
    for ( i = 0; i < 7; i++)
    {
        k = i;
        for ( j = i + 1, st = w[k] ; j < 7; j++)
        {
            if(strcmp(w[j],st)<0) k = j;
        }
        if(k != i)
        {
            st = w[i]; w[i] = w[k]; w[k] = st;
        }
    }
    printf("排序后\n");
    for ( i = 0; i < 7; i++)
    {
        printf("%p\t%s\n",w[i],w[i]);
    }*/

    return 0;

}

void avg(void)
{
    int score[10],*p,max = 0, min = 0,sum = 0;
    int i;
    printf("input score  a number of 10\n");
    p  = score;
    for ( i = 0; i < 10; i++)
    {
        scanf("%d", p++);
    }
    p  = score;
    max = min = score[0];
    for ( i = 0; i < 10; i++)
    {
        if(*(p + i) > max) max = *(p + i);
        if(*(p + i) < min) min = *(p + i);
        sum += score[i];
    }
    printf("avg：%.1lf",(sum - max -min)/8.0);
}
void calroot(double a, double b, double c)
{
    double derta = 0 , x1 = 0, x2 = 0;
    derta = (b * b) - (4 * a * c);
    if(derta >= 0)
    {
        if(derta > 0)
        {
            x1 = -b + sqrt(derta) / (2.0 * a);
            x2 = -b - sqrt(derta) / (2.0 * a);
            printf("方程有两个不相等的实根分别为：%3.2lf , %3.2lf ",x1,x2);
        }else
        {
            x1 = (-b) / (2.0 * a);
            printf("方程有两个相等的实根分别为：%3.2lf ",x1);
        }
    }
    else printf("此方程无解");


}
double sum(int n)
{
    double i, sum = 0;
    if( n > 5)
    for ( i = 1; i <=n; i++)
    {
        sum += pow(-1,i+1) / i;
    }
    return sum;
}
int getgcd(int a,int b)
{
        int c = 1, t;
        if(a < b)
        {
            t = a;
            a = b;
            b = t;
        }
        while(c)
        {
             c = a % b;
              a = b;
              b = c;
        }
    
    return a;
}
int gcd(int a,int b)

 { 
     if(a%b==0)
     return b;
         else;
         return gcd(b,a%b);
 }
long h1(int n)
{   
    int product;
    if(n == 1) product = 1;
    else    product = n * h1(n-1); 
    return product;
}
long h2(int m)
{
    long s=0;
    int i;
    for(i=1;i<=m;i++)
    s=s+h1(i);
    return s;
}
int sushu(int x)    //是素数返回1 否则返回0
{
    //int i, k = 1;
    //if( x == 1 ) k = 0;
    //for ( i = 2; i <= x/2; i++)
    //{
    //    if( x % i == 0) k=0;
    //}
    //return k;

    //int m, i,flag = 1;
    //m = (int)sqrt((double)x);
    //if( x == 1 ) return 0;
    //for ( i = 2; i <= m; i++)
    //{
    //    if( x % i == 0) 
    //    {
    //        flag = 0;
    //        return 0;
    //    }
    //}
    //if(flag) return 1;

    int i;
    for ( i = 2; i < x; i++)
        if(x % i == 0) break;
        if(x == 1) return 0;
        if(i >= x) return 1;
        else  return 0;
    
}
void inverse(char str[])
{
    char t;
    int i, j;
    for ( i = 0 , j = strlen(str); i < strlen(str)/2; i++, j--)
    {
        t = str[i];
        str[i] = str[j - 1];
        str[j  - 1] = t;
    }
}
void space(char str[])
{
    int i ;
    for ( i = strlen(str); i > 0; i--)
    {
        str[2 * i] = str [i];
        str[2 * i - 1] = ' ';
    }
}
//void sort(char(*s)[6])
//{
//    int i,j;
//    char *t,temp[6];
//    t = temp;
//    for ( i = 0; i < 9; i++)
//    {
//        for ( j = 0; j < 9 - i; j++)
//        {
//            if(strcmp(s[j],s[j+1])>0)
//            {
//                strcpy(t,s[j]);
//                strcpy(s[j],s[j+1]);
//                strcpy(s[j+1],t);
//            }
//        }
//    }
//}
int fun(int x)
{
    int t1 = 1, t2 = 1, t3 = 0 , i;
        int y = 0;
        if(x == 1 || x == 2) 
        {y = 1;}
        else if(x>2)
        {
            for ( i = 3; i <= x; i++)
            {
                t3 = t1 + t2;
                t1 = t2 ;
                t2 = t3;
            }
            return t3;
        }
        return y;
}
int del(int a[], int n, int x)
{
    int p ,i ;
    p = 0;
    while (x >= a[p] && p<n)
    p = p + 1 ;
    for ( i = p - 1; i < n; i++)
    a[i] = a[i + 1];
    n = n - 1;
    return n;
}
int ReadScore(int score[])
{
    int i = -1;
    do
    {
        i++;
        printf("Input score");
        scanf("%d" , &score[i]);
    } while (score[i] >= 0);
    return i;
}
void PrintScore(int score[],int n)
{
    int i;
    for ( i = 0; i < n; i++)
    {
        printf("%3d",score[i]);
    }
    printf("\n");
}
void AscendingSort(int a[],int n)
{
    int i , j , k ,temp;
    for ( i = 0; i < n-1; i++)
    {
        k  = i;
        for ( j = i+1; j < n; j++)
        {
            if(a[j] < a[k]) k = j;
        }
            if(k != i)
            {
                temp = a[i];
                a[i] = a[k];
                a[k] = temp;
            }
    }

    //for ( i = 0; i < n -1 ; i++)
    //{
    //    for ( j = 1; j < n ; j++)
    //    {
    //        if(a[j] < a[j-1]) 
    //        {
    //            temp = a[j];
    //            a[j] = a[j-1];
    //            a[j-1] = temp;
    //        }
    //    }
    //}
    //for ( i = 0; i < n - 1 ; i++)
    //{
    //    for ( j = 0 ; j < n - 1 - i; j++)
    //    {
    //        if(a[j] > a[j+1]) 
    //        {
    //            temp = a[j + 1];
    //            a[j+1] = a[j];
    //            a[j] = temp;
    //        }
    //    }
    //}
}
void DescendingSort(int a[],int n)
{
    int i , j , k ,temp;
    for ( i = 0; i < n-1; i++)
    {
        k  = i;
        for ( j = i+1; j < n; j++)
        {
            if(a[j] > a[k]) k = j;
        }
            if(k != i)
            {
                temp = a[k];
                a[k] = a[i];
                a[i] = temp;
            }
    }
}
int ReadScore1(int score[])
{
    int i = -1;
    do
    {
        i++;
        printf("Input score");
        scanf("%d" , &score[i]);
    } while (score[i] >= 0);
    return i;
}
void PrintScore1(int score[],int n)
{
    int i;
    for ( i = 0; i < n; i++)
    {
        printf("%3d",score[i]);
    }
    printf("\n");
}
int AscendingSort1(int a,int b)
{
    return a < b; //为真，则按升序排序
}
int DescendingSort1(int a,int b)
{
    return a > b; //为真，则按降序排序
}
void SelectingSort(int a[], int n, int (*compare)(int a,int b))
{
    int i , j , k ,temp;
    for ( i = 0; i < n-1; i++)
    {
        k = i;
        for ( j = i + 1; j < n; j++)
        {
            if((*compare)(a[j] , a[k])) k =  j;
        }
        if(k != i)
        {
            temp = a[k];
            a[k] = a[i];
            a[i] = temp;
        }
    }
}