实验五
一.
1)
#include <stdio.h> #define N 4 int main() { int x[N] = { 1,9,8,4 }; int i; int* p; //方式1 for (i = 0;i < N;++i) printf("%d", x[i]); printf("\n"); //方式2（1） for (p = x;p < x + N;++p) printf("%d", *p); printf("\n"); //方式2（2） p = x; for (i = 0;i < N;++i) printf("%d", *(p + i)); printf("\n"); //方式2（3） p = x; for (i = 0;i < N;++i) printf("%d", p[i]); printf("\n"); return 0; }
2)
#include <stdio.h> int main() { int x[2][4] = { {1,9,8,4},{2,0,4,9} }; int i, j; int* p; int(*q)[4]; for (i = 0;i < 2;++i) { for (j = 0;j < 4;++j) printf("%d", x[i][j]); printf("\n"); } for (p = &x[0][0], i = 0;p < &x[0][0] + 8;++p, ++i) { printf("%d", *p); if ((i + 1) % 4 == 0) printf("\n"); } for (q = x;q < x + 2;++q) { for (j = 0;j < 4;++j) printf("%d", *(*q + j)); printf("\n"); } return 0; }
二.
1)
#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_s(tmp,N,s1); strcpy_s(s1,N,s2); strcpy_s(s2,N,tmp); printf("\nafter swap:\n"); printf("s1:%s\n", s1); printf("s2:%s\n", s2); return 0; }
问题1：24，占用的字节数 ，有效字符个数除空格外
问题2：不能，因为s1是常量
问题3：是
2)
#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; }
问题1：字符串的初始地址，第一个单词的长度，字符串的字符数
问题2：可以
问题3：交换是地址
三.
#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++) ; }
四.
#include <stdio.h> #define N 80 int fun(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; }
五.
#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'; }
六.
1）
#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; } }
2）
#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; } } }
七.
#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; } // 函数定义 // 功能: 检查指针str指向的身份证号码串形式上是否合法。 // 形式合法，返回1，否则，返回0 int check_id(char* str) { // 补足函数实现 // ... char* p; p = str; while ((*p >= '0' && *p <= '9') || *p == 'X') p++; if (*p == '\0' && strlen(str) == 18) return 1; else return 0; }
八.
未成功
