华清远见25072班C++学习假期10.5作业
1、数组练习
- 选择题
1.1、若有定义语句:int a[3][6]; ,按在内存中的存放顺序,a 数组的第10个元素是D
- a[0][4] B) a[1][3] C)a[0][3] D)a[1][4]
1.2、有数组 int a[5] = {10,20,30,40,50}, 以下表达式编译错误是___A__ ___B____。
A) a ++ ;
B) a[5] = 20 ;
C) a + 20 ;
D) (a-3, a[3]) ;
1.3、以下错误的定义语句是 ___C____
A)int x[][3] = {{0},{1},{1,2,3}};
B)int x[4][3] = {{1,2,3},{1,2,3},{1,2,3},{1,2,3}};
C)int x[4][] = {{1,2,3},{1,2,3},{1,2,3},{1,2,3}};
D)int x[][3] = {1,2,3,4};
1.4、设int i,x[3][3]={1,2,3,4,5,6,7,8,9};则下面语句
for(i=0;i<3;i++)
printf(″%d, ″,x[i][2-i]);
的输出结果是 D
A)1, 4, 7 B)1, 5, 9 C)3, 6, 9 D)3, 5, 7
1.5、表达式“sizeof(int [1][2])/sizeof(int)”的值为__A___。
A) 2 B) 3 C) 4 D) 5
1.6有以下程序
#include main()
{ char s[]="012xy\07s34f4w2";
int i,n=0;
for(i=0;s[i]!=0;i++)
if(s[i]>='0'&&s[i]<='9')
n++;
printf("%d\n",n);
}
程序运行后的输出结果是_____C_______
A)0 B)3 C)7 D)8
1.7、有以下程序
#include <stdio.h>
main( )
{ char s[ ]=”wstuv”; printf(“%c\n”,*s+2);
}
程序运行后的输出结果是C
A)t B) tuv C)y D)出错
1.8 数组 int a[5] = {10, 20, 30, 40,50}, 有以下语句,其输出___C____
printf(“%d\n”, *(&a +1) );
A) 20 B) 30 C) 随机值 D)编译报错
1.9 有以下程序
# include <stdio.h>
int main()
{ int s[12]={1,2,3,4,4,3,2,1,1,1,2,3}, c[5]={0,0,0,0,0}, i ;
for(i=0;i<12;i++) c[s[i]]++ ;
for(i=1;i<5;i++) printf(“%d,”,c[i]); printf(“\n”);
}A
A) 4 ,3, 3, 2 B) 2 , 3, 4, 4
C) 1, 2, 3 ,4 D ) 4, 4, 2 ,3
1.10 有数组 int a[3][4] = {10,20,30,40,50,60,70,80,90,100,110,120},执行以下语句输出的是_______D________
printf(“%d\n”, *(*a+2) + 3 );
A) 语句有错 B) 120 C) 30 D) 33
- 填空题
2.1、有以下程序
#include <stdio.h>
main( )
{ int i,n[ ]={0,0,0,0,0};
for(i=1;i<=4;i++)
{n[i]=n[i-1]*3+1;
printf(“%d”,n[i]);}
}
程序运行后输出结果是 _____141340_____
2.2、执行以下程序的输出结果是_3715 .
#include <stdio.h>
int main()
{ int i,n[4]={1,0,0,0};
for(i=1;i<=3;i++)
{ n[i]=n[i-1]*2+1; printf("%d",n[i]); }
}
2.3、下面程序运行的结果为___358______。
main()
{
int x[5],i;
x[0] = 1;x[1] = 2;
for(i = 2;i<5;i++) x[i] = x[i-1] + x[i-2];
for(i = 2;i<5;i++) printf(“%d”,x[i]);
}
2.4、有以下程序
#include <sthio.h>
int main()
{
int arr[] = {1,3,5,7,2,4,6,8}, i, start ;
scanf(“%d”, &start);
for(i=0,i<7,i+=2)
printf(“%d”,arr[(start+i)%5]);
}
若在程序运行时输入整数 10 <回车>,则输出结果为____726___
2.5下面程序运行的结果为___54820______。
#include "stdio.h"
main()
{ int i,j,a[]={0,2,8,4,5};
printf("\n");
for(i=1;i<=5;i++)
{ j=5-i;
printf("%2d",a[j]);
}
}
2.6有以下程序
#include <stdio.h>
int main()
{ int n[2],i,j;
for(i=0;i<2;i++) n[i]=0; for(i=0;i<2;i++)
for(j=0;j<2;j++) n[j]=n[i]+1;
printf(“%d\n”,n[1]);
}
程序运行后的输出结果是 3
3、编程题
3.1、 一个班10个学生的成绩,存放在一个一维数组中,要求找出其中成绩最高的学生的成绩和该生的序号。试编程。(试着用下标法和地址法两种方法表示数组)
#include <iostream>
using namespace std;
const int STUDENT_COUNT = 10; // 学生数量
// 下标法实现
void findMaxByIndex()
{int scores[STUDENT_COUNT];int maxScore, maxIndex;// 输入成绩cout << "【下标法】请输入" << STUDENT_COUNT << "个学生的成绩:" << endl;for (int i = 0; i < STUDENT_COUNT; ++i) {cin >> scores[i];}// 初始化最高成绩和索引maxScore = scores[0];maxIndex = 0;// 遍历数组(下标访问)for (int i = 1; i < STUDENT_COUNT; ++i){if (scores[i] > maxScore){maxScore = scores[i];maxIndex = i;}}cout << "下标法结果:最高成绩为" << maxScore << ",对应学生序号(从1开始):" << maxIndex + 1 << endl;
}// 地址法实现(指针访问)
void findMaxByAddress()
{int scores[STUDENT_COUNT];int maxScore, maxIndex;int* p; // 指针用于访问数组// 输入成绩(指针访问)cout << "【地址法】请输入" << STUDENT_COUNT << "个学生的成绩:" << endl;for (p = scores; p < scores + STUDENT_COUNT; ++p){cin >> *p; // 通过指针解引用赋值}// 初始化最高成绩和索引maxScore = *scores; // 等价于scores[0]maxIndex = 0;// 遍历数组(指针访问)for (p = scores + 1; p < scores + STUDENT_COUNT; ++p){if (*p > maxScore) {maxScore = *p;maxIndex = p - scores; // 指针差值即下标}}cout << "地址法结果:最高成绩为" << maxScore << ",对应学生序号(从1开始):" << maxIndex + 1 << endl;
}
int main() {findMaxByIndex();findMaxByAddress();return 0;
}
3.2、有5个学生上4门课程,要求输入全部学生的各门课程成绩,然后输出各门课程的平均成绩,并按照各个学生的平均成绩排序(成绩最高的学生排在数组最前面,最低学生排在数组最后面的行) (试着用下标法和地址法两种方法表示数组)。
#include <iostream>
#include <iomanip>
using namespace std;const int STUDENT_COUNT = 5; // 学生数量
const int COURSE_COUNT = 4; // 课程数量// 学生信息结构体
struct Student
{int scores[COURSE_COUNT]; // 各科成绩float avg; // 个人平均成绩
};// 下标法实现
void solveByIndex()
{Student students[STUDENT_COUNT];float courseAvg[COURSE_COUNT] = {0}; // 每门课的平均分// 1. 输入成绩并计算个人平均分和课程总分cout << "\n【下标法】请输入" << STUDENT_COUNT << "个学生的" << COURSE_COUNT << "门成绩(每行" << COURSE_COUNT << "个整数):" << endl;for (int i = 0; i < STUDENT_COUNT; ++i){float sum = 0; // 个人总分for (int j = 0; j < COURSE_COUNT; ++j){cin >> students[i].scores[j]; // 下标访问成绩sum += students[i].scores[j];courseAvg[j] += students[i].scores[j]; // 累加课程总分}students[i].avg = sum / COURSE_COUNT; // 计算个人平均分}// 2. 计算每门课程的平均分for (int j = 0; j < COURSE_COUNT; ++j){courseAvg[j] /= STUDENT_COUNT;}// 3. 按个人平均分降序排序(冒泡排序,下标访问)for (int i = 0; i < STUDENT_COUNT - 1; ++i){for (int j = 0; j < STUDENT_COUNT - 1 - i; ++j){if (students[j].avg < students[j + 1].avg){swap(students[j], students[j + 1]); // 交换学生信息}}}// 4. 输出结果cout << "【下标法】课程平均分:" << endl;for (int j = 0; j < COURSE_COUNT; ++j){cout << "第" << j + 1 << "门课:" << fixed << setprecision(1) << courseAvg[j] << " ";}cout << "\n按个人平均分降序排序后的学生成绩:" << endl;for (int i = 0; i < STUDENT_COUNT; ++i){cout << "学生" << i + 1 << "成绩:";for (int j = 0; j < COURSE_COUNT; ++j){cout << students[i].scores[j] << " ";}cout << ",平均分:" << students[i].avg << endl;}
}// 地址法实现(指针访问)
void solveByAddress()
{Student students[STUDENT_COUNT];float courseAvg[COURSE_COUNT] = {0};Student* pStu; // 指向学生的指针int* pScore; // 指向成绩的指针// 1. 输入成绩并计算个人平均分和课程总分(指针访问)cout << "\n【地址法】请输入" << STUDENT_COUNT << "个学生的" << COURSE_COUNT << "门成绩(每行" << COURSE_COUNT << "个整数):" << endl;for (pStu = students; pStu < students + STUDENT_COUNT; ++pStu){float sum = 0;pScore = pStu->scores; // 指向当前学生的成绩数组for (int j = 0; j < COURSE_COUNT; ++j){cin >> *(pScore + j); // 指针访问成绩sum += *(pScore + j);courseAvg[j] += *(pScore + j);}pStu->avg = sum / COURSE_COUNT;}// 2. 计算每门课程的平均分for (int j = 0; j < COURSE_COUNT; ++j){courseAvg[j] /= STUDENT_COUNT;}// 3. 按个人平均分降序排序(冒泡排序,指针访问)for (pStu = students; pStu < students + STUDENT_COUNT - 1; ++pStu){for (Student* p = students; p < students + STUDENT_COUNT - 1 - (pStu - students); ++p){if (p->avg < (p + 1)->avg){swap(*p, *(p + 1)); // 交换指针指向的学生信息}}}// 4. 输出结果(指针访问)cout << "【地址法】课程平均分:" << endl;for (int j = 0; j < COURSE_COUNT; ++j){cout << "第" << j + 1 << "门课:" << fixed << setprecision(1) << courseAvg[j] << " ";}cout << "\n按个人平均分降序排序后的学生成绩:" << endl;for (pStu = students; pStu < students + STUDENT_COUNT; ++pStu){cout << "学生" << (pStu - students) + 1 << "成绩:";pScore = pStu->scores;for (int j = 0; j < COURSE_COUNT; ++j){cout << *(pScore + j) << " ";}cout << ",平均分:" << pStu->avg << endl;}
}int main() {solveByIndex();solveByAddress();return 0;
}
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