实验五
task1
#include <stdio.h> #define N 5 void input(int x[], int n); void output(int x[], int n); void find_min_max(int x[], int n, int *pmin, int *pmax); int main() { int a[N]; int min, max; printf("录入%d个数据:\n", N); input(a, N); printf("数据是: \n"); output(a, N); printf("数据处理...\n"); find_min_max(a, N, &min, &max); printf("输出结果:\n"); printf("min = %d, max = %d\n", min, max); 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"); } void find_min_max(int x[], int n, int *pmin, int *pmax) { int i; *pmin = *pmax = x[0]; for(i = 0; i < n; ++i) if(x[i] < *pmin) *pmin = x[i]; else if(x[i] > *pmax) *pmax = x[i]; }
1.找出最大最小值
2.指向x【0】

#include <stdio.h> #define N 5 void input(int x[], int n); void output(int x[], int n); int *find_max(int x[], int n); int main() { int a[N]; int *pmax; printf("录入%d个数据:\n", N); input(a, N); printf("数据是: \n"); output(a, N); printf("数据处理...\n"); pmax = find_max(a, N); printf("输出结果:\n"); printf("max = %d\n", *pmax); return 0; } void input(int x[], int n) { int i; for(i = 0; i < n; ++i) scanf("%d", &x[i]); } v oid output(int x[], int n) { int i; for(i = 0; i < n; ++i) printf("%d ", x[i]); printf("\n"); } int *find_max(int x[], int n) { int max_index = 0; int i; for(i = 0; i < n; ++i) if(x[i] > x[max_index]) max_index = i; return &x[max_index]; }
1.返回最大值的地址
2.可以

task2
#include <stdio.h> #include <string.h> #define N 80 int main() { char s1[N] = "Learning makes me happy"; char s2[N] = "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; }
1.80字节 s1占用80字节的内存空间 s1有效字符长度
2.能替换
3.交换了

#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; }
1.存放字符串的初始位置 计算s1在内存中占用的字节数 统计字符串中字符个数
2可以替换
3.交换的两字符串的地址 字符串没有交换

task3
#include <stdio.h> int main() { int x[2][4] = {{1, 9, 8, 4}, {2, 0, 4, 9}}; int i, j; int *ptr1; int(*ptr2)[4]; printf("输出1: 使用数组名、 下标直接访问二维数组元素\n"); for (i = 0; i < 2; ++i) { for (j = 0; j < 4; ++j) printf("%d ", x[i][j]); printf("\n"); } printf("\n输出2: 使用指针变量ptr1(指向元素)间接访问\n"); for (ptr1 = &x[0][0], i = 0; ptr1 < &x[0][0] + 8; ++ptr1, ++i) { printf("%d ", *ptr1); if ((i + 1) % 4 == 0) printf("\n"); } printf("\n输出3: 使用指针变量ptr2(指向一维数组)间接访问\n"); for (ptr2 = x; ptr2 < x + 2; ++ptr2) { for (j = 0; j < 4; ++j) printf("%d ", *(*ptr2 + j)); printf("\n"); } return 0; }
1.指针
2.数组

task4
#include <stdio.h> #define N 80 void replace(char *str, char old_char, char new_char); int main() { char text[N] = "Programming is difficult or not, it is a question."; printf("原始文本: \n"); printf("%s\n", text); replace(text, 'i', '*'); printf("处理后文本: \n"); printf("%s\n", text); return 0; } void replace(char *str, char old_char, char new_char) { int i; while(*str) { if(*str == old_char) *str = new_char; str++; } }
1.将所有字符old_char替换为字符new_char
2.可以

task5
#include <stdio.h> #define N 80 char *str_trunc(char *str, char x); int main() { char str[N]; char ch; while(printf("输入字符串: "), gets(str) != NULL) { printf("输入一个字符: "); ch = getchar(); printf("截断处理...\n"); str_trunc(str, ch); // 函数调用 printf("截断处理后的字符串: %s\n\n", str); getchar(); } return 0; } char *str_trunc(char *str, char x){ char *p = str; while (*p != '\0'){ if (*p == x){ *p ='\0'; break; } p++; } return str; }
1.无法输出 吃掉回车键

task6
#include <stdio.h> #include <string.h> #define N 5 int check_id(char *str); // 函数声明 int main() { char *pid[N] = {"31010120000721656X", "3301061996X0203301", "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){ int len = strlen(str); if (len != 18){ return 0; } int i; for (i = 0;i <17;i++){ if (!(str[i] >= '0' && str[i] <= '9')){ return 0; } } if (str[17] != 'x'){ if (!(str[i] >= '0' && str[i] <= '9')){ return 0; } } return 1; }

task7
#define _CRT_SECURE_NO_WARNINGS #include <stdio.h> #include <string.h> #include<stdlib.h> typedef struct { char name[20]; // 姓名 char phone[12]; // 手机号 int vip; // 是否为紧急联系人,是取1;否则取0 } Contact; // 函数声明 void set_vip_contact(Contact x[], int n, char name[]); // 设置紧急联系人 void output(Contact x[], int n); // 输出x中联系人信息 void display(Contact x[], int n); // 按联系人姓名字典序升序显示信息,紧急联系人最先显示 #define N 10 int main() { Contact list[N] = { {"刘一", "15510846604", 0}, {"陈二", "18038747351", 0}, {"张三", "18853253914", 0}, {"李四", "13230584477", 0}, {"王五", "15547571923", 0}, {"赵六", "18856659351", 0}, {"周七", "17705843215", 0}, {"孙八", "15552933732", 0}, {"吴九", "18077702405", 0}, {"郑十", "18820725036", 0} }; int vip_cnt, i; char name[20]; printf("显示原始通讯录信息: \n"); output(list, N); printf("\n输入要设置的紧急联系人个数: "); scanf_s("%d", &vip_cnt); printf("输入%d个紧急联系人姓名:\n", vip_cnt); for (i = 0; i < vip_cnt; ++i) { scanf_s("%s", name); set_vip_contact(list, N, name); } printf("\n显示通讯录列表:(按姓名字典序升序排列,紧急联系人最先显示)\n"); display(list, N); system("pause"); return 0; } void set_vip_contact(Contact x[], int n, char name[]) { int i; for (i = 0; i < n; ++i) { if (!strcmp(x[i].name, name)) x[i].vip = 1; } } void display(Contact x[], int n) { int i, j, k; Contact t; for (i = 0; i < n; i++) { for (j = 0; j < n - i - 1; j++) { if (strcmp(x[j].name, x[j + 1].name) > 0) { t = x[j]; x[j] = x[j + 1]; x[j + 1] = t; } } } for (i = n - 1; i >= 0; i--) { for (k = 0; k < i; ++k) { if (x[i].vip) { for (j = i; j > 0; j--) { t = x[j]; x[j] = x[j - 1]; x[j - 1] = t; } } } } output(x, n); } void output(Contact x[], int n) { int i; for (i = 0; i < n; ++i) { printf("%-10s%-15s", x[i].name, x[i].phone); if (x[i].vip) printf("%5s", "*"); printf("\n"); } }


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