实验5
试验任务1_1
程序源代码
#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; }
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试验任务1_2
程序源代码
#include <stdio.h> int main() { int x[2][4] = {{1, 9, 8, 4}, {2, 0, 4, 9}}; int i, j; int *p; // 指针变量，存放int类型数据的地址 int(*q)[4]; // 指针变量，指向包含4个int型元素的一维数组 // 使用数组名、下标访问二维数组元素 for (i = 0; i < 2; ++i) { for (j = 0; j < 4; ++j) printf("%d", x[i][j]); printf("\n"); } // 使用指针变量p间接访问二维数组元素 for (p = &x[0][0], i = 0; p < &x[0][0] + 8; ++p, ++i) { printf("%d", *p); if ((i + 1) % 4 == 0) printf("\n"); } // 使用指针变量q间接访问二维数组元素 for (q = x; q < x + 2; ++q) { for (j = 0; j < 4; ++j) printf("%d", *(*q + j)); printf("\n"); } return 0; }
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试验任务2_1
程序源代码
#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; }
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试验任务2_2
程序源代码
#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; }
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存放的是地址。计算类型长度。统计的是其所包含的字符串的长度。
可以。这个是直接在地址上进行修改。
交换的是各自的地址。没有。
实验任务3
程序源代码
#include<stdio.h>
#include<stdlib.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);
system("pause");
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++)
;}
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实验任务4
程序源代码
#include<stdio.h> #include<stdlib.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"); } system("pause"); 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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实验任务5
程序源代码
#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--; while (*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'; }
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试验任务6_1
程序源代码
#include<stdio.h> #include<string.h> #include<stdlib.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]); system("pause"); 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; } }
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试验任务6_2
程序源代码
#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, 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; } } }
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交换的是指针变量的值
实验任务7
程序源代码
#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; int i; p = str; while((*p >= '0' && *p <= '9')||*p=='X') p++; if(*p == '\0' && strlen(str) == 18) return 1; else return 0; }
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实验任务8
程序源代码
#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); // 函数调用 printf("%s\n", words); printf("对编码后的英文文本解码: "); decoder(words); // 函数调用 printf("%s\n", words); return 0; } void encoder(char *s) { while(*s) { if(*s >= 65 && *s <= 90|| *s >= 97&& *s <= 122) { *s = *s + 1; s++; continue; } else if(*s == 90|| *s == 122) { *s = *s - 25; s++; continue; } s++; } return; } void decoder(char *s) { while(*s) { if(*s >= 66 && *s <= 90 || *s >= 98 && *s <= 122) { *s = *s - 1; s++; continue; } else if(*s == 65|| *s == 97) { *s = *s + 25; s++; continue; } s++; } return; }
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