实验六
task1_1.c
#include<stdio.h> #define N 4 int main() { int x[N]={1,9,8,4}; int i; int *p; for(i=0;i<N;++i) printf("%d",x[i]); printf("\n"); for(p=x;p<x+N;++p) printf("%d",*p); printf("\n"); p=x; for(i=0;i<N;++i) printf("%d",*(p+i)); printf("\n"); p=x; for(i=0;i<N;++i) printf("%d",p[i]); printf("\n"); return 0; }
task1_2.c
#include<stdio.h> #define N 4 int main() { char x[N]={'1','9','8','4'}; int i; char *p; for(i=0;i<N;++i) printf("%c",x[i]); printf("\n"); for(p=x;p<x+N;++p) printf("%c",*p); printf("\n"); p=x; for(i=0;i<N;++i) printf("%c",*(p+i)); printf("\n"); p=x; for(i=0;i<N;++i) printf("%c",p[i]); printf("\n"); return 0; }
2004;2001;数据类型不同
task2_1.c
#include<stdio.h> int main() { int x[2][4]={{1,9,8,4},{2,0,2,2}}; 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; }
task2_2.c
#include<stdio.h> int main() { char x[2][4]={{'1','9','8','4'},{'2','0','2','2'}}; int i,j; char *p; char (*q)[4]; for(i=0;i<2;++i) { for(j=0;j<4;++j) printf("%c",x[i][j]); printf("\n"); } for(p=&x[0][0],i=0;p<&x[0][0]+8;++p,++i) { printf("%c",*p); if((i+1)%4==0) printf("\n"); } for(q=x;q<x+2;++q) { for(j=0;j<4;++j) printf("%c",*(*q+j)); printf("\n"); } return 0; }
2004,2016;2001,2004;数据类型不同，且++q表示到下一行，增加了四个数的地址值。
task3_1.c
#include<stdio.h> #include<string.h> #define N 80 int main() { char s1[]="C,I love u."; char s2[]="C,I hate u."; 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; }
12;sizeof(s1)计算的是字节数，包括了结束符；strlen(s1)计算实际长度，不包括结束符；
不能；是
task3_2.c
#include<stdio.h> #include<string.h> #define N 80 int main() { char *s1="C,I love u."; char *s2="C,I hate u."; 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; }
s1字符串的地址；sizeof(s1)计算的是指针变量所占字节数；strlen(s1)统计的是实际长度；
交换的是地址；没有
task4.c
#include<stdio.h> #include<string.h> #define N 5 int check_id(char *str); int main() { char *pid[N]={"31010120000721656X", "330106199609203301", "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 i; if(strlen(str)!=18) return 0; for(i=0;i<18;i++) { if(str[i]=='X'||(str[i]<='9'&&str[i]>='0')) continue; else return 0; } return 1; }
task5.c
#include<stdio.h> #include<string.h> #define N 80 int is_palindrome(char *s); int main() { char str[N]; int flag; printf("Enter a string:\n"); gets(str); flag=is_palindrome(str); if(flag) printf("YES\n"); else printf("NO\n"); return 0; } int is_palindrome(char *s) { int i; long n,m; n=strlen(s); m=n/2; for(i=0;i<m-1;i++) if(s[i]!=s[n-i-1]) return 0; return 1; }
task6.c
#include<stdio.h> #define N 80 void encoder(char *s); void decoder(char *s); 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); printf("%s\n",words); printf("对编码后的英文文本解码:"); decoder(words); printf("%s\n",words); return 0; } void encoder(char *s) { int i; for(i=0;i<N;i++) { if(*(s+i)=='z'||*(s+i)=='Z') *(s+i)-=25; else if((*(s+i)>='a'&&*(s+i)<'z')||(*(s+i)>='A'&&*(s+i)<'Z')) *(s+i)+=1; } } void decoder(char *s) { int i; for(i=0;i<N;i++) { if(*(s+i)=='a'||*(s+i)=='A') *(s+i)+=25; else if((*(s+i)>'a'&&*(s+i)<='z')||(*(s+i)>'A'&&*(s+i)<='Z')) *(s+i)-=1; } }
