5
1
源代码
#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); getchar(); getchar(); 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]; }
找到最大元素，最小元素
输入第一个数据
结果
#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]); } void 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]; }
结果
返回最大元素的地址
2
源代码
#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); getchar(); getchar(); return 0; }
结果
80 数组大小 数组长度
能
交换
#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); getchar(); getchar(); return 0; }
结果
s1地址的大小
s1字符串的长度
能
源代码直接定义一个指向字符串的指针
换的代码先定义一个指针，再指向字符串
地址
没有
3
源代码
#include <stdio.h> int main() { int x[2][4] = {{1, 9, 8, 4}, {2, 0, 4, 9}}; int i, j; int *ptr1; // 指针变量，存放int类型数据的地址 int(*ptr2)[4]; // 指针变量，指向包含4个int元素的一维数组 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"); } getchar(); getchar(); return 0; }
结果
ptr为指向含4个元素的一维整形数组的指针变量
ptr 为由4个指向整形的指针变量组成的指针数组
4
源代码
#include <stdio.h> #define N 80 void replace(char *str, char old_char, char new_char); // 函数声明 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', '*'); // 函数调用 注意字符形参写法，单引号不能少 printf("处理后文本: \n"); printf("%s\n", text); return 0; } // 函数定义 void replace(char *str, char old_char, char new_char) { int i; while(*str) { if(*str == old_char) *str = new_char; str++; } }
结果
将i替换为#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'; } p++; } return str; }
结果
抵消回车键带来的影响
6
源代码
int check_id(char *str) { int len = strlen(str); if (len!= 18) return 0; int sum = 0; int weight[] = {7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2}; char checksum[] = {'1', '0', 'X', '9', '8', '7', '6', '5', '4', '3', '2'}; for (int i = 0; i < 17; ++i) { if (str[i] < '0' || str[i] > '9') return 0; sum += (str[i] - '0') * weight[i]; } int index = sum % 11; if (str[17] == checksum[index]) return 1;
getchar();
getchar(); return 0; }
结果
实验7
源代码
#include <stdio.h> #define N 80 void encoder(char *str, int n); // 函数声明 void decoder(char *str, int n); // 函数声明 int main() { char words[N]; int n; printf("输入英文文本: "); gets(words); printf("输入n: "); scanf("%d", &n); printf("编码后的英文文本: "); encoder(words, n); // 函数调用 printf("%s\n", words); printf("对编码后的英文文本解码: "); decoder(words, n); // 函数调用 printf("%s\n", words); getchar(); getchar(); return 0; } void encoder(char *str, int n) { int i; for(i=0;str[i]!='\0';i++){ if(str[i]>='a'&&str[i]<='z'){ str[i]=(str[i]-'a'+n)%26+'a'; } else if(str[i]>='A'&&str[i]<='Z'){ str[i]=(str[i]-'A'+n)%26+'A'; } } } void decoder(char *str, int n) { int i; for(i=0;str[i]!='\0';i++){ if(str[i]>='a'&&str[i]<='z'){ str[i]=(str[i]-'a'-n+26)%26+'a'; } else if(str[i]>='A'&&str[i]<='Z'){ str[i]=(str[i]-'A'-n+26)%26+'A'; } } }
结果
实验八
源代码
#include <stdio.h> #include<string.h> int main(int argc, char *argv[]) { int i; int j; char* temp; for(i = 1; i < argc; i++){ for(j=1;j<argc-i;j++){ if(strcmp(argv[j],argv[j+1])>0){ temp = argv[j]; argv[j] = argv[j+1]; argv[j+1] = temp; } } } for(i = 1; i < argc; ++i) printf("hello, %s\n", argv[i]); getchar(); return 0; }
结果
