1. 实验任务1
task1_1.c
#include <stdio.h> #define N 4 int main() { int x[N] = {1, 9, 8, 4}; int i; int *p; // 方式1:通过数组名和下标遍历输出数组元素 for (i = 0; i < N; ++i) printf("%d", x[i]); printf("\n"); // 方式2:通过指针变量遍历输出数组元素 (写法1) for (p = x; p < x + N; ++p) printf("%d", *p); printf("\n"); // 方式2:通过指针变量遍历输出数组元素(写法2) p = x; for (i = 0; i < N; ++i) printf("%d", *(p + i)); printf("\n"); // 方式2:通过指针变量遍历输出数组元素(写法3) p = x; for (i = 0; i < N; ++i) printf("%d", p[i]); printf("\n"); return 0; }
实验结果截图
task1_2.c
实验结果截图
2. 实验任务2
task2_1.c
#include <stdio.h> #include <string.h> #define N 80 int main() { char s1[] = "Learning makes me happy"; char s2[] = "Learning makes me sleepy"; char tmp[N]; printf("sizeof(s1) vs. strlen(s1): \n"); printf("sizeof(s1) = %d\n", sizeof(s1)); printf("strlen(s1) = %d\n", strlen(s1)); printf("\nbefore swap: \n"); printf("s1: %s\n", s1); printf("s2: %s\n", s2); printf("\nswapping...\n"); strcpy(tmp, s1); strcpy(s1, s2); strcpy(s2, tmp); printf("\nafter swap: \n"); printf("s1: %s\n", s1); printf("s2: %s\n", s2); return 0; }
实验结果截图
问题1:数组s1的大小是多少?sizeof(s1)计算的是什么?strlen(s1)统计的是什么?
答:数组s1的大小为80,
sizeof(s1)计算的是数组s1的长度(包括字符串结尾的'\0'),是统计字符串s1的长度(不包括字符串结尾的'\0')。
问题2:line7代码,能否替换成以下写法?如果不能,写出原因。
答:不能。在定义数组的时候,需要同时给数组分配好存储空间,并初始化数组元素的值。而第二种写法中,只给s1定义了一个空数组,但并没有为它分配存储空间,也没有初始化数组元素的值,因此这种写法是非法的。
问题3:line20-22执行后,字符数组s1和s2中的内容是否交换?
答:是。字符数组s1中原本存储的字符串"Learining makes me happy"被复制到了临时数组tmp中,然后再从字符数组s2中复制字符串"Learining makes me sleepy"到s1中,最后从临时数组中复制"Learining makes me happy"到s2中,因此两个字符数组s1和s2中的内容被成功交换。
task2_2.c
#include <stdio.h> #include <string.h> #define N 80 int main() { char *s1 = "Learning makes me happy"; char *s2 = "Learning makes me sleepy"; char *tmp; printf("sizeof(s1) vs. strlen(s1): \n"); printf("sizeof(s1) = %d\n", sizeof(s1)); printf("strlen(s1) = %d\n", strlen(s1)); printf("\nbefore swap: \n"); printf("s1: %s\n", s1); printf("s2: %s\n", s2); printf("\nswapping...\n"); tmp = s1; s1 = s2; s2 = tmp; printf("\nafter swap: \n"); printf("s1: %s\n", s1); printf("s2: %s\n", s2); return 0; }
运行结果截图
问题1:指针变量s1中存放的是什么?sizeof(s1)计算的是什么?strlen(s1)统计的是什么?
答:指针变量s1中存放的是字符串"Learning makes me happy"的地址。sizeof(s1)计算的是字符串"Learning makes me happy"的地址的大小。strlen(s1)统计的是字符串"Learning makes me happy"的长度(不包括字符串结尾的'\0')。
问题2:line7代码能否替换成下面的写法?对比task2_1.c中的line7, 描述二者的语义区别。
答:能。line7的含义是将常量字符串首地址赋值给字符指针,task2_1.c中的line7是用字符串对字符数组初始化。
问题3:line20-line22,交换的是什么?字符串常量"Learning makes me happy"和字符串常 量"Learning makes me sleepy"在内存存储单元中有没有交换?
答:line20-line22交换的是指向字符串常量"Learning makes me happy"和字符串常量"Learning makes me sleepy"的指针。字符串常量"Learning makes me happy"和字符串常 量"Learning makes me sleepy"在内存存储单元中没有交换。
3. 实验任务3
task3.c
#include<stdio.h> void str_cpy(char *target,const char *source); void str_cat(char *str1,char *str2); int main() { char s1[80],s2[20] = "1984"; str_cpy(s1,s2); puts(s1); str_cat(s1,"Animal Farm"); puts(s1); return 0; } void str_cpy(char *target,const char *source) { while (*target++=*source++); } void str_cat(char *str1,char *str2) { while (*str1) str1++; while (*str1++=*str2++); }
实验结果截图
4. 实验任务4
task.c
#include<stdio.h> #define N 80 int func(char *); int main() { char str[80]; while(gets(str)!=NULL) { if(func(str)) printf("yes\n"); else printf("no\n"); } return 0; } int func(char *str) { char *begin,*end; begin = end = str; while(*end) end++; end--; while(begin<end) { if(*begin!=*end) return 0; else { begin++; end--; } } return 1; }
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5. 实验任务5
task.c
#include<stdio.h> #define N 80 void func(char *); int main() { char s[N]; while(scanf("%s",s)!=EOF) { func(s); puts(s); } return 0; } void func(char *str) { int i; char *p1,*p2,*p; p1 = str; while(*p1=='*') p1++; p2 = str; while(*p2) p2++; p2--; p = str; i=0; while(p<p1) { str[i] = *p; p++; i++; } while(p<=p2) { if(*p!='*') { str[i] = *p; i++; } p++; } while(*p!='\0') { str[i] = *p; p++; i++; } str[i] = '\0'; }
实验结果截图
6. 实验任务6
task6_1.c
#include<stdio.h> #include<string.h> void sort(char *name[],int n); int main() { char *course[4] = {"C Program","C++ Object Oriented Program","Operating System","Data Structure and Algorithms"}; int i; sort(course,4); for(i=0;i<4;i++) printf("%s\n",course[i]); return 0; } void sort(char *name[],int n) { int i,j; char *tmp; for(i=0;i<n-1;++i) for(j=0;j<n-1-i;++j) if(strcmp(name[j],name[j+1])>0) { tmp = name[j]; name[j] = name[j+1]; name[j+1] = tmp; } }
答:交换的是指针。
实验结果截图
task6_2.c
#include<stdio.h> void sort(char *name[],int n); int main() { char *course[4] = {"C Program","C++ Object Oriented Program","Operating System","Data Structure and Algorithms"}; int i; sort(course,4); for(i=0;i<4;i++) printf("%s\n",course[i]); return 0; } void sort(char *name[],int n) { int i,j,k; char *tmp; for(i=0;i<n-1;i++) { k=i; for(j=i+1;j<n;j++) if(strcmp(name[j],name[k])<0) k=j; if(k!=i) { tmp = name[i]; name[i] = name[k]; name[k] = tmp; } } }
实验结果截图
交换的是内存中字符串的存储位置。
7. 实验任务7
task.c
#include<stdio.h> #include<string.h> #define N 5 int check_id(char *str); //函数声明 int main() { char *pid[N] = {"31010120000721656X","330106199609203301","53010220051126571","510104199211197977","53010220051126133Y"}; int i; for(i=0;i<N;++i) if(check_id(pid[i]))//函数调用 printf("%s\tTrue\n",pid[i]); else printf("%s\tFalse\n",pid[i]); return 0; } int check_id(char *str) { char *p; p = str; while((*p >= '0' && *p <= '9')||*p=='X') p++; if(*p == '\0' && strlen(str) == 18) return 1; else return 0; }
实验结果截图
8. 实验任务8
task.c
#include<stdio.h> #define N 80 void encoder(char *s); //函数声明 void decoder(char *s); //函数声明 int main() { char words[N]; printf("输入英文文本:"); gets(words); printf("编码后的英文文本:"); encoder(words); printf("%s\n",words); printf("对编码后的英文文本解码:"); decoder(words); printf("%s\n",words); return 0; } void encoder(char *s) { while(*s!='\0') { if(*s >= 65 && *s <= 90|| *s >= 97&& *s <= 122) { *s = *s + 1; s++; continue; } else if(*s == 'z'|| *s == 'Z') { *s = *s - 25; s++; continue; } s++; } } void decoder(char *s) { while(*s) { if(*s >= 66 && *s <= 90 || *s >= 98 && *s <= 122) { *s = *s - 1; s++; continue; } else if(*s == 'A'|| *s == 'a') { *s = *s + 25; s++; continue; } s++; } }
实验结果截图
标签:int,s2,s1,char,实验,printf,makes From: https://www.cnblogs.com/xsq1201/p/17372647.html