实验四

实验任务1

程序源码

#include<stdio.h>
#include<stdlib.h>
#define N 4

int main(){
    int a[N] = {2, 0, 2, 3};
    char b[N] = {'2', '0', '2', '3'};
    int i;

    printf("sizeof(int) = %d\n:", sizeof(int));
    printf("sizeof(char) = %d\n", sizeof(char));
    printf("\n");

    for(i = 0; i < N; ++i)
        printf("%p：%c\n", &b[i], b[i]);

    printf("\n");

    printf("a = %p\n", a);
    printf("b = %p\n", b);

    system("pause");
    return 0;

}

 

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讨论：

int型数组a是连续存放的，每个元素占用4个字节

char型数组b是连续存放的，每个元素占用1个字节

数组名a对应的值和&a[0]一样，数组名b对应的值和&b[0]一样

程序源码

#include<stdio.h>
#include<stdlib.h>
#define N 2
#define M 3

int main(){
    int a[N][M] = {{1, 2, 3}, {4, 5, 6}};
    char b[N][M] = {{'1', '2', '3'}, {'4', '5', '6'}};
    int i, j;

    for(i = 0; i < N; ++i)
        for(j = 0; j < M; ++j)
            printf("%p：%d\n", &a[i][j], a[i][j]);

    printf("\n");

    printf("a = %p\n", a);
    printf("a[0] = %p\n", a[0]);
    printf("a[1] = %p\n", a[1]);
    printf("\n");

    for(i = 0; i < N; ++i)
        for(j = 0; j < M; ++j)
            printf("%p：%c\n", &b[i][j], b[i][j]);
    printf("\n");

    printf("b = %p\n", b);
    printf("b[0] = %p\n", b[0]);
    printf("b[1] = %p\n", b[1]);
    printf("\n");

    system("pause");
    return 0;

}

 

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讨论：

数组a,在内存中是“按行连续存放的‘’，每个元素占4个字节单元

一样

数组b,在内存中是“按行连续存放的‘’，每个元素占1个字节单元

一样

a[0]和a[1]差12个字节，b[0]和b[1]差3个字节

实验任务2

程序源码

#include<stdio.h>
#include<stdlib.h>
#include<string.h>

#define N 80

void swap_str(char s1[N], char s2[N]);
void test1();
void test2();

int main(){
    printf("测试1：用两个一维数组，实现两个字符串交换\n");
    test1();

    printf("\n测试：用二维数组，实现两个字符串交换\n");
    test2();

    system("pause");
    return 0;

}

void test1(){
    char views1[N] = "hey, C, I hate u.";
    char views2[N] = "hey, C, I love u.";

    printf("交换前：\n");
    puts(views1);
    puts(views2);

    swap_str(views1, views2);

    printf("交换后：\n");
    puts(views1);
    puts(views2);
}

void test2(){
    char views[2][N] = {"hey, C, I hate u.", "hey, C, I, love u."};

    printf("交换前：\n");
    puts(views[0]);
    puts(views[1]);

    swap_str(views[0], views[1]);

    printf("交换后：\n");
    puts(views[0]);
    puts(views[1]);

}

void swap_str(char s1[N], char s2[N]){
    char tmp[N];

    strcpy(tmp, s1);
    strcpy(s1, s2);
    strcpy(s2, tmp);

}

 

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讨论

实验任务3

程序源码

#include<stdio.h>
#include<stdlib.h>
#define N 80

int count(char x[]);

int main(){
    char words[N+1];
    int n;

    while(gets(words) != NULL){
        n = count(words);
        printf("单词数：%d\n\n", n);
    }

    system("pause");
    return 0;

}

int count(char x[]){
    int i;
    int word_flag = 0;
    int number = 0;

    for(i= 0; x[i] != '\0'; i++){
        if(x[i] == ' ')
            word_flag = 0;
        else if(word_flag == 0){
            word_flag = 1;
            number++;
        }
    }

    return number;
}

 

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程序源码

#include<stdio.h>
#include<stdlib.h>
#define N 1000

int main(){
    char line[N];
    int word_len;
    int max_len;
    int end;
    int i;

    while(gets(line) != NULL){
        word_len = 0;
        max_len = 0;
        end = 0;

        i =0;
        while(1){
            while(line[i] == ' '){
                word_len = 0;
                i++;
            }

            while(line[i] != '\0' && line[i] != ' '){
                word_len++;
                i++;
            }

            if(max_len < word_len){
                max_len = word_len;
                end = i;
            }

            if(line[i] == '\0')
                break;
        }

        printf("最长单词：");
            for(i = end - max_len; i < end; ++i)
                printf("%c", line[i]);
            printf("\n\n");
        }

        system("pause");
        return 0;
    }

 

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实验任务4

程序源码

#include<stdio.h>
#include<stdlib.h>
#define N 5

void input(int x[], int n);
void output(int x[], int n);
double average(int x[], int n);
void bubble_sort(int x[], int n);

int main(){
    int scores[N];
    double ave;

    printf("录入%d个分数：\n", N);
    input(scores, N);

    printf("\n输出课程分数：\n", N);
    output(scores, N);

    printf("\n课程分数处理：计算均分,排序...\n");
    ave = average(scores, N);
    bubble_sort(scores, N);

    printf("\n输出课程平均分：%.2f\n", ave);
    printf("\n输出课程分数(高->低)：\n");
    output(scores, N);

    system("pause");
    return 0;
}

void input(int x[], int n){
    int i;

    for(i = 0; i < n; ++i)
        scanf("%d", &x[i]);
}

void output(int x[], int n){
    int i;

    for(i = 0; i < n; ++i)
        printf("%d ", x[i]);
    printf("\n");
}

double average(int x[], int n){
    int i;
    double s = 0;

    for(i = 0; i < n; ++i)
        s = s + x[i];
    return s / n;
}

void bubble_sort(int x[], int n){
    int i, j, t;

    for(i = 0; i < n-1; ++i)
        for(j = 0; j < n-i-1; ++j)
            if(x[j] > x[j+1]){
            t = x[j];
            x[j] = x[j+1];
            x[j+1] = t;
            }
}

 

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实验任务5

程序源码

#include<stdio.h>
#include<stdlib.h>
#define N 100
void dec2n(int x, int n);

int main(){
    int x;

    printf("输入一个十进制整数：");
    while(scanf("%d", &x) != EOF){
        dec2n(x, 2);
        dec2n(x, 8);
        dec2n(x, 16);

        printf("\n输入一个十进制整数：");
    }

    system("pause");
    return 0;
}

void dec2n(int x, int n){
    char num[N];
    char str[N]="0123456789ABCDEF";
    int i=0,j,t;
    while(x!=0){
        t=x%n;
        x=x/n;
        num[i]=str[t];
        i++;
    }
    j=i;
    for(i=j-1;i>=0;i--)
    printf("%c",num[i]);
    printf("\n");
} 

 

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实验任务6

程序源码

#include <stdio.h>
#include<stdlib.h>
#define N 100
#define M 4

void output(int x[][N], int n);          
void rotate_to_right(int x[][N], int n); 


int main() {
    int t[][N] = {{21, 12, 13, 24},
                  {25, 16, 47, 38},
                  {29, 11, 32, 54},
                  {42, 21, 33, 10}};

    printf("原始矩阵:\n");
    output(t, M); 

    rotate_to_right(t, M); 

    printf("变换后矩阵:\n");
    output(t, M); 

    system("pause");
    return 0;
}
void output(int x[][N], int n) {
    int i, j;

    for (i = 0; i < n; ++i) {
        for (j = 0; j < n; ++j)
            printf("%4d", x[i][j]);

        printf("\n");
    }
}
void rotate_to_right(int x[][N], int n){
    int i,j,t;
    for(i=0;i<n;i++){
        t=x[i][n-1];
        for(j=n-1;j>0;j--){
            x[i][j]=x[i][j-1];
        }
        x[i][0]=t;
    }
}

 

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实验任务7

程序源码

#include <stdio.h>
#include<stdlib.h>
#define N 80

void replace(char x[], char old_char, char new_char);

int main() {
    char text[N] = "Rose will bloom all the time.";

    printf("原始文本: \n");
    printf("%s\n", text);

    replace(text, 'l', '#'); 
    printf("处理后文本: \n");
    printf("%s\n", text);

    system("pause");
    return 0;
}
void replace(char x[], char old_char, char new_char) {
    int i;

    for (i = 0; x[i] != '\0'; ++i)
        if (x[i] == old_char)
            x[i] = new_char;
}

 

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程序源码

#include <stdio.h>
#include<stdlib.h>
#define N 80

int main() {
    char str[N], ch;
    int i;

    printf("输入字符串: ");
    gets(str);

    printf("输入一个字符: ");
    ch = getchar();

    printf("截断处理......");

    i = 0;
    while (str[i] != '\0') {
        if (str[i] == ch){
            str[i+1]='\0';
            break;}
            i++;
    }
    str[i] ='\0' ; 

    printf("\n截断处理后字符串: %s\n", str);

    system("pause");
    return 0;
}

 

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讨论：replace()的功能：用新的字符替换旧的字符

'\0'是空字符，也是字符串的终止字符

实验任务8

程序源码

#include <stdio.h>
#include<stdlib.h>
#include <string.h>

#define N 5
#define M 20

void bubble_sort(char str[][M], int n); // 函数声明

int main() {
    char name[][M] = {"Bob", "Bill", "Joseph", "Taylor", "George"};
    int i;

    printf("输出初始名单:\n");
    for (i = 0; i < N; i++)
        printf("%s\n", name[i]);

    printf("\n排序中...\n");
    bubble_sort(name, N);  

    printf("\n按字典序输出名单:\n");
    for (i = 0; i < N; i++)
        printf("%s\n", name[i]);

    system("pause");
    return 0;
}
void bubble_sort(char str[][M], int n){
    int i,j;
    char k[M];
    for(i=0;i<5;i++)
       for(j=0;j<n-i-1;j++)
           if(strcmp(str[j],str[j+1])>0){
                 strcpy(k,str[j]);
                 strcpy(str[j],str[j+1]);
                 strcpy(str[j+1],k);
           }
}

 

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