实验5
实验任务1.1
源代码
1 #include<stdio.h> 2 #define N 5 3 4 void input(int x[],int n); 5 void output(int x[],int n); 6 void find_min_max(int x[],int n, int *pmin,int *pmax); 7 8 int main(){ 9 int a[N]; 10 int min,max; 11 12 printf("录入%d个数据:\n",N); 13 input(a,N); 14 15 printf("数据是：\n"); 16 output(a,N); 17 18 printf("数据处理...\n"); 19 find_min_max(a,N,&min,&max); 20 21 printf("输出结果：\n"); 22 printf("min=%d,max=%d\n",min,max); 23 24 return 0; 25 } 26 27 void input(int x[],int n){ 28 int i; 29 for(i=0;i<n;++i) 30 scanf("%d",&x[i]); 31 } 32 33 void output(int x[],int n){ 34 int i; 35 for(i=0;i<n;++i) 36 printf("%d",x[i]); 37 printf("\n"); 38 } 39 40 void find_min_max(int x[],int n, int *pmin,int *pmax){ 41 int i; 42 *pmin=*pmax=x[0]; 43 for(i=0;i<n;++i) 44 if(x[i]<*pmin) 45 *pmin=x[i]; 46 else if(x[i]>*pmax) 47 *pmax=x[i]; 48 }
运行结果
1,找到最大值和最小值
2.指向min和max
1.2
源代码
1 #include<stdio.h> 2 #define N 5 3 4 void input(int x[],int n); 5 void output(int x[],int n); 6 int *find_max(int x[],int n); 7 8 int main(){ 9 int a[N]; 10 int *pmax; 11 12 printf("录入%d个数据:\n",N); 13 input(a,N); 14 15 printf("数据是：\n"); 16 output(a,N); 17 18 printf("数据处理...\n"); 19 pmax=find_max(a,N); 20 21 printf("输出结果：\n"); 22 printf("max=%d\n",*pmax); 23 return 0; 24 } 25 26 void input(int x[],int n){ 27 int i; 28 for(i=0;i<n;++i) 29 scanf("%d",&x[i]); 30 } 31 32 void output(int x[],int n){ 33 int i; 34 for(i=0;i<n;++i) 35 printf("%d ",x[i]); 36 printf("\n"); 37 } 38 int *find_max(int x[],int n){ 39 int i; 40 int max_index=0; 41 for(i=1;i<n;++i) 42 if(x[i]>x[max_index]) 43 max_index=i; 44 45 return &x[max_index]; 46 }
1 #include<stdio.h> 2 #define N 5 3 4 void input(int x[],int n); 5 void output(int x[],int n); 6 int *find_max(int x[],int n); 7 8 int main(){ 9 int a[N]; 10 int *pmax; 11 12 printf("录入%d个数据:\n",N); 13 input(a,N); 14 15 printf("数据是：\n"); 16 output(a,N); 17 18 printf("数据处理...\n"); 19 pmax=find_max(a,N); 20 21 printf("输出结果：\n"); 22 printf("max=%d\n",*pmax); 23 return 0; 24 } 25 26 void input(int x[],int n){ 27 int i; 28 for(i=0;i<n;++i) 29 scanf("%d",&x[i]); 30 } 31 32 void output(int x[],int n){ 33 int i; 34 for(i=0;i<n;++i) 35 printf("%d ",x[i]); 36 printf("\n"); 37 } 38 39 int *find_max(int x[],int n){ 40 int i; 41 int *ptr=&x[0]; 42 for(i=1;i<n;++i) 43 if(x[i]>*ptr) 44 *ptr=x[i]; 45 46 return ptr; 47 }
运行结果
1.返回最大值的地址
2.可以
实验任务2.1
源代码
1 #include <stdio.h> 2 #include <string.h> 3 #define N 80 4 5 int main() { 6 char s1[] = "Learning makes me happy"; 7 char s2[] = "Learning makes me sleepy"; 8 char tmp[N]; 9 10 printf("sizeof(s1) vs. strlen(s1): \n"); 11 printf("sizeof(s1) = %d\n", sizeof(s1)); 12 printf("strlen(s1) = %d\n", strlen(s1)); 13 14 printf("\nbefore swap: \n"); 15 printf("s1: %s\n", s1); 16 printf("s2: %s\n", s2); 17 18 printf("\nswapping...\n"); 19 strcpy(tmp, s1); 20 strcpy(s1, s2); 21 strcpy(s2, tmp); 22 23 printf("\nafter swap: \n"); 24 printf("s1: %s\n", s1); 25 printf("s2: %s\n", s2); 26 27 return 0; 28 }
运行结果
1.24个字节，s1变量所占内存，s1字符串的长度
2.不能，s1是数组的起始地址，不能赋值
3.交换
2.2
源代码
1 #include <stdio.h> 2 #include <string.h> 3 #define N 80 4 5 int main() { 6 char *s1 = "Learning makes me happy"; 7 char *s2; 8 s2= "Learning makes me sleepy"; 9 char *tmp; 10 11 printf("sizeof(s1) vs. strlen(s1): \n"); 12 printf("sizeof(s1) = %d\n", sizeof(s1)); 13 printf("strlen(s1) = %d\n", strlen(s1)); 14 15 printf("\nbefore swap: \n"); 16 printf("s1: %s\n", s1); 17 printf("s2: %s\n", s2); 18 19 printf("\nswapping...\n"); 20 tmp=s1; 21 s1=s2; 22 s2=tmp; 23 24 printf("\nafter swap: \n"); 25 printf("s1: %s\n", s1); 26 printf("s2: %s\n", s2); 27 28 return 0; 29 }
运行结果
1.字符串起始地址，s1变量所占内存，字符串的长度
2.可以，2.1中是定义一个字符数组，存放learning，2.2是定义一个指向字符的指针变量，存放字符串的起始地址
3.交换的是指针指向的地址，内存单元中没有交换。
实验任务3
源代码
1 #include <stdio.h> 2 3 int main() { 4 int x[2][4]={{1,9,8,4},{2,0,4,9}}; 5 int i,j; 6 int *ptr1; 7 int (*ptr2)[4]; 8 9 printf("输出1：使用数组名、下标直接访问二维数组元素\n"); 10 for (i = 0; i < 2; ++i) { 11 for (j = 0; j < 4; ++j) 12 printf("%d ", x[i][j]); 13 printf("\n"); 14 } 15 printf("输出2：使用使用指向元素的指针间接访问二维数组元素\n"); 16 for(ptr1=&x[0][0],i=0;ptr1<&x[0][0]+8;++ptr1,++i){ 17 printf("%d ",*ptr1); 18 19 if((i+1)%4==0) 20 printf("\n"); 21 } 22 printf("输出3：使用指向一位数组的指针变量间接访问二维数组元素\n"); 23 for(ptr2=x;ptr2<x+2;++ptr2){ 24 for(j=0;j<4;++j) 25 printf("%d ",*(*ptr2+j)); 26 printf("\n"); 27 } 28 29 return 0; 30 }
运行结果
实验任务4.1
源代码
1 #include <stdio.h> 2 #define N 80 3 4 void replace(char *str, char old_char, char new_char); 5 6 int main() { 7 char text[N] = "c programming is difficult or not, it is a question."; 8 9 printf("原始文本: \n"); 10 printf("%s\n", text); 11 12 replace(text, 'i', '*'); 13 14 printf("处理后文本: \n"); 15 printf("%s\n", text); 16 17 return 0; 18 } 19 20 void replace(char *str, char old_char, char new_char) { 21 int i; 22 23 while(*str) { 24 if(*str == old_char) 25 *str = new_char; 26 str++; 27 } 28 }
运行结果
4.2
源代码
1 #include <stdio.h> 2 #define N 80 3 4 void str_trunc(char *str, char x); 5 6 int main() { 7 char str[N]; 8 char ch; 9 10 printf("输入字符串: "); 11 gets(str); 12 13 printf("输入一个字符: "); 14 ch = getchar(); 15 16 printf("截断处理...\n"); 17 str_trunc(str, ch); 18 19 printf("截断处理后的字符串: %s\n", str); 20 21 } 22 23 void str_trunc(char *str, char x) { 24 while(*str) { 25 if(*str == x) 26 *str='\0';// blank1 27 28 str++;// blank2 29 } 30 }
运行结果
实验任务5.1
源代码
1 #include <stdio.h> 2 #include <string.h> 3 void sort(char *name[], int n); 4 5 int main() { 6 char *course[4] = {"C Program", 7 "C++ Object Oriented Program", 8 "Operating System", 9 "Data Structure and Algorithms"}; 10 int i; 11 12 sort(course, 4); 13 14 for (i = 0; i < 4; i++) 15 printf("%s\n", course[i]); 16 17 return 0; 18 } 19 20 void sort(char *name[], int n) { 21 int i, j; 22 char *tmp; 23 24 for (i = 0; i < n - 1; ++i) 25 for (j = 0; j < n - 1 - i; ++j) 26 if (strcmp(name[j], name[j + 1]) > 0) { 27 tmp = name[j]; 28 name[j] = name[j + 1]; 29 name[j + 1] = tmp; 30 } 31 }
运行结果
5.2
源代码
1 #include <stdio.h> 2 #include <string.h> 3 void sort(char *name[], int n); 4 5 int main() { 6 char *course[4] = {"C Program", 7 "C++ Object Oriented Program", 8 "Operating System", 9 "Data Structure and Algorithms"}; 10 int i; 11 12 sort(course, 4); 13 for (i = 0; i < 4; i++) 14 printf("%s\n", course[i]); 15 16 return 0; 17 } 18 19 void sort(char *name[], int n) { 20 int i, j, k; 21 char *tmp; 22 23 for (i = 0; i < n - 1; i++) { 24 k = i; 25 for (j = i + 1; j < n; j++) 26 if (strcmp(name[j], name[k]) < 0) 27 k = j; 28 29 if (k != i) { 30 tmp = name[i]; 31 name[i] = name[k]; 32 name[k] = tmp; 33 } 34 } 35 }
运行结果
交换的是指针变量的值。
实验任务6
源代码
1 #include <stdio.h> 2 #include <string.h> 3 #define N 5 4 5 int check_id(char *str); // 函数声明 6 7 int main() { 8 char *pid[N] = {"31010120000721656X", 9 "330106199609203301", 10 "53010220051126571", 11 "510104199211197977", 12 "53010220051126133Y"}; 13 int i; 14 15 for (i = 0; i < N; ++i) 16 if (check_id(pid[i])) // 函数调用 17 printf("%s\tTrue\n", pid[i]); 18 else 19 printf("%s\tFalse\n", pid[i]); 20 21 return 0; 22 } 23 24 25 int check_id(char *str) { 26 if(strlen(str)==18){ 27 while(*str!='\0') 28 str++; 29 str--; 30 if(*str=='X'||(*str>='0'&&*str<='9')) 31 return 1; 32 else 33 return 0; 34 } 35 else 36 return 0; 37 }
运行结果
实验任务7
源代码
1 #include <stdio.h> 2 #define N 80 3 void encoder(char *str); // 函数声明 4 void decoder(char *str); // 函数声明 5 6 int main() { 7 char words[N]; 8 9 printf("输入英文文本: "); 10 gets(words); 11 12 printf("编码后的英文文本: "); 13 encoder(words); // 函数调用 14 printf("%s\n", words); 15 16 printf("对编码后的英文文本解码: "); 17 decoder(words); // 函数调用 18 printf("%s\n", words); 19 20 return 0; 21 } 22 23 /*函数定义 24 功能：对s指向的字符串进行编码处理 25 编码规则： 26 对于a~z或A~Z之间的字母字符，用其后的字符替换; 其中，z用a替换，Z用A替换 27 其它非字母字符，保持不变 28 */ 29 void encoder(char *str) { 30 int i=0; 31 char x[N]={'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','a'}; 32 char y[N]={'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z','A'}; 33 while(*str){ 34 i=0; 35 if(*str>='a'&&*str<='z'){ 36 while(*str!=x[i++]&&i<26); 37 *str=x[i]; 38 } 39 i=0; 40 if(*str>='A'&&*str<='Z'){ 41 while(*str!=y[i++]&&i<26); 42 *str=y[i]; 43 } 44 str++; 45 } 46 } 47 48 49 void decoder(char *str) { 50 int i=0; 51 char x[N]={'z','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'}; 52 char y[N]={'Z','A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'}; 53 while(*str){ 54 i=1; 55 if(*str>='a'&&*str<='z'){ 56 while(*str!=x[i++]&&i<=26); 57 *str=x[i-2]; 58 } 59 i=1; 60 if(*str>='A'&&*str<='Z'){ 61 while(*str!=y[i++]&&i<=26); 62 *str=y[i-2]; 63 } 64 str++; 65 } 66 67 }
运行结果
实验任务8
