实验五
#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.功能是找到一列数组中最大和最小值
2.x[0]的地址
#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]; }

1.找到最大值的地址;返回最大值的地址
2.可以
#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;内存大小;s1长度
2.不能,s1是起始地址不能赋值
3.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); return 0; }

1.L的地址,str1占用的字节数,有效字符数
2.可以,2.1中是将地址赋值给了指针,2.2中是字符串赋值数组
3.交换地址;不交换
#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"); } return 0; }

1.指向数组指针
2.指向储存指针的数组
#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++; } }

1.将old_char替换成new_char
2.可以
#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); printf("截断处理后的字符串:%s\n\n",str); getchar(); } return 0; } char*str_trunc(char *str,char x){ int i=0; while(*str!='\0'){ if(*str==x){ *str='\0'; } str++; i++; } }

处理换行符
#include<stdio.h> #include<string.h> #define N 5 int check_id(char *str); int main() { char *pid[N] = {"31010120000721656X", "3301061996X0203301", "53010220051126571", "510104199211197977", "53010220051126133Y"}; int i; for(i=0;i<N;i++) if(check_id(pid[i])) printf("%s\tTrue\n",pid[i]); else printf("%s\tFalse\n",pid[i]); return 0; } int check_id(char *str){ int cnt=0; if(strlen(str)!=18) return 0; while(cnt<17){ if(*str>='0'&&*str<='9'){ cnt++; str++; } else return 0; } while(cnt=18){ if(*str=='X'||(*str>='0'&&*str<='9')) return 1; else return 0; } }

#include<stdio.h> #define N 80 void encoder(char *str,int n); void decoder(char *str,int n); int main(){ char words[N]; int n; printf("请输入文本:"); gets(words); printf("输入n:"); scanf("%d",&n); printf("编码后的英文文本:"); encoder(words,n); printf("%s\n",words); printf("对编码后的英文文本解码:"); decoder(words,n); printf("%s\n",words); return 0; } void encoder(char *str,int n){ while(*str!='\0'){ if(*str>='a'&&*str<='z'){ *str='a'+(*str+n-97)%26; } else if(*str>='A'&&*str<='Z'){ *str='A'+(*str+n-65)%26; } str++; } } void decoder(char *str,int n){ while(*str!='\0'){ if(*str>='a'&&*str<='z'){ if(*str-97-n>=0) *str='a'+*str-97-n; else *str='z'-(97+n-*str)%26+1; } else if(*str>='A'&&*str<='Z'){ if(*str-65-n>=0) *str='A'+*str-65-n; else *str='Z'-(65+n-*str)%26+1; } str++; } }

#include<stdio.h> #include<string.h> void com(int n,char *s[]); int main(int argc,char *argv[]){ int i; com(argc-1,argv+1); for(i=1;i<argc;++i) printf("hello,%s\n",argv[i]); return 0; } void com(int n,char *s[]){ int i,j; char *temp; for(i=0;i<n-1;i++){ for(j=0;j<n-1-i;j++){ if(strcmp(s[j],s[j+1])>0){ temp=s[j]; s[j]=s[j+1]; s[j+1]=temp; } } } }

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