慕课-程序设计与算法（大学先修课)-郭炜-第八九周练习题

1.下面程序片段的输出结果是 Hello ,请填空

#include <iostream>using namespace std;int main() {    char s[] = "Hello";      char * p;    for(p=s;*p!=NULL;p++)        cout << * p ;    return 0;}

2.下面程序输出结果是 Tesla Tes 请填空

#include <iostream>using namespace std;void Print(const char * p1, const char * p2) {      for(;p1<p2;p1++)            cout << * p1;}int main()  {    const char * s = "Tesla123";    Print(s,s+5);    cout << endl;    Print(s,s+3);    cout << endl;    return 0;}

3.程序填空，使得输出结果为：
1,4,9,16,25,
h,e,l,l,o,!,

#include <iostream>using namespace std;void ForEach(void * a, int width, int num,void f(void *)){    for(int i = 0;i < num; ++i)         f((char*)a+width*i);}void PrintSquare(void * p){    int * q = (int*)p;    int n = *q;    cout << n * n << ",";}void PrintChar(void * p) {    char * q = (char*)p;    cout << *q << ",";}int main(){    int a[5] = {1,2,3,4,5};    char s[] = "hello!";    ForEach(a,sizeof(int),5,PrintSquare);     cout << endl;    ForEach(s,sizeof(char),6,PrintChar);    return 0;}

4.Memcpy之一
输入：
第一行是整数t
接下来是t个整数
再接下来是t个不带空格的字符串，长度不超过20
输出：
按原样输出t个整数和t个字符串

#include <iostream>using namespace std;void Memcpy(char * src,char * dest,int n){    for(int i=0;i<n;i++)    {        dest[i]=src[i];    }}int Strlen(char * s){       int i;    for( i = 0; s[i]; ++i);    return i;}int main()  {    int a;    char s1[30];    char s2[30];    int t;    cin >> t;    for(int i = 0;i < t; ++i) {        cin >> a;        int b = 99999999;        Memcpy((char*)&a,(char *) &b,sizeof(int));        cout << b << endl;    }    for(int i = 0;i < t; ++i) {        cin >> s1;        Memcpy(s1,s2,Strlen(s1)+1);        cout << s2 << endl;    }    return 0;}

5.程序填空，使其输出结果是： 1,2,3,4, 10,12,14,16, 18,20,11,12,

#include <iostream>using namespace std;void Double(int * p, int n){    for(int i = 0;i < n; ++i)        p[i] *= 2;}int main(){    int a[3][4] = { { 1,2,3,4},{5,6,7,8},                    { 9,10,11,12 } };    Double(a[1],6);    for(int i = 0;i < 3; ++i) {        for(int j = 0; j < 4; ++j)            cout << a[i][j] << ",";        cout << endl;     }    return 0;}

6.Memcpy之二
输入：
第一行是整数n (1<=n<=10)
第二行是 n个整数
输出：
先原序输出输入数据中的n个整数
然后再输出:
1,2,3,4,5,1,2,3,4,5,
123434567
167896789

#include <iostream>using namespace std;void Memcpy( void * src, void * dest, int size){char * dest1 = (char *)dest;    char * src1 = (char *)src;    for (int i = size-1; i >= 0; i--)        dest1[i] = src1[i];}void Print(int * p,int size){    for(int i = 0;i < size; ++i)        cout << p[i] << ",";    cout << endl;}int main(){    int a[10];    int n;    cin >> n;    for(int i = 0;i < n; ++i)        cin >> a[i];    int b[10] = {0};    Memcpy(a,b,sizeof(a));    Print(b,n);    int c[10] = {1,2,3,4,5,6,7,8,9,10};    Memcpy(c,c+5,5*sizeof(int)); //将c的前一半拷贝到后一半     Print(c,10);    char s[10] = "123456789";    Memcpy(s+2,s+4,5); //将s[2]开始的5个字符拷贝到s[4]开始的地方     cout << s << endl;    char s1[10] = "123456789";    Memcpy(s1+5,s1+1,4); //将s1[5]开始的4个字符拷贝到s1[1]开始的地方     cout << s1 << endl;    return 0;}

7.编写一个 MyMax函数，可以用来求任何数组中的最大值 使得程序按要求输出

#include <iostream>using namespace std;void *MyMax(void *a, unsigned int b, int n, int(*fun)(void *, void *)){    int judge;    int *max = (int *)a;    for (int i = 1; i<n ; ++i)    {        judge = fun(max, (int *)a+i);        if (judge < 0)            max = (int *)a + i;    }    return max;}int Compare1(void * n1,void * n2){    int * p1 = (int * )n1;    int * p2 = (int * )n2;    return ((*p1)%10) - ((*p2)%10);}int Compare2(void * n1,void * n2){    int * p1 = (int * )n1;    int * p2 = (int * )n2;    return *p1 - *p2;}#define eps 1e-6int Compare3(void * n1,void * n2){    float * p1 = (float * )n1;    float * p2 = (float * )n2;    if( * p1 - * p2 > eps)        return 1;    else if(* p2 - * p1 > eps)        return -1;    else        return 0; }int main(){    int t;    int a[10];    float d[10];    cin >> t;    while(t--) {        int n;        cin >> n;        for(int i = 0;i < n; ++i)            cin >> a[i];        for(int i = 0;i < n; ++i)            cin >> d[i];        int * p = (int *) MyMax(a,sizeof(int),n,Compare1);        cout << * p << endl;        p = (int *) MyMax(a,sizeof(int),n,Compare2);        cout << * p << endl;        float * pd = (float * )MyMax(d,sizeof(float),n,Compare3);        cout << * pd << endl;    }    return 0;}

8.指向指针的指针，程序填空使得输出指定结果

#include <iostream>using namespace std;int main(){    int x,y,z;    x = 10;    y = 20;    z = 30;    int * a[3]  = { &x, &y,&z};    for(int *(*p)=a; p < a + 3; ++p)             cout<< * (*p) << endl;    return 0;}

9.填写内存交换函数 SwapMemory，使得程序输出指定结果

#include <iostream>using namespace std;void SwapMemory(void * m1,void * m2, int size){if (size > 5)    {        int *m11 = (int *)m1;        int *m22 = (int *)m2;        int temp;        for (int i = 0; i < 5; i++)        {            temp = *(m11 + i);            *(m11 + i) = *(m22 + i);            *(m22 + i) = temp;        }    }    else    {        char *m11 = (char *)m1;        char *m22 = (char *)m2;        char temp;        for (int i = 0; i < size; i++)        {            temp = *(m11 + i);            *(m11 + i) = *(m22 + i);            *(m22 + i) = temp;        }    }}void PrintIntArray(int * a,int n){    for(int i = 0;i < n; ++i)        cout << a[i] << ",";    cout << endl;}int main(){    int a[5] = {1,2,3,4,5};    int b[5] = {10,20,30,40,50};    SwapMemory(a,b,5 * sizeof(int));    PrintIntArray(a,5);    PrintIntArray(b,5);    char s1[] = "12345";    char s2[] = "abcde";    SwapMemory(s1,s2,5);    cout << s1 << endl;    cout << s2 << endl;    return 0;}