实验六
#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"); return 0; }
地址:2004
#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\n", *p); printf("\n"); p = x; for(i=0; i<N; ++i) printf("%c", *(p+i)); printf("\n"); for(i=0; i<N; ++i) printf("%c", p[i]); printf("\n"); return 0; }
地址:2001
#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; }
地址:2004 2016
#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(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; }
地址:2001 2004
#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; }
Q1
s1大小:13
sizeof(s1)计算的是对象所占的内存空间
strlen(s1)统计的是字符串中的字符个数
Q2
不能替换
Q3
s1 s2内容交换了
#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; }
Q1
s1存放的是"C, I love u."的地址,sizeof(s1)计算的是s1所占的内存空间,strlen(s1)统计的是字符串的字符个数
Q2
可以替换
Q3
交换了地址
没有交换
#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) { for(i=0;i<18;++i) { if((str[i]>='0'&&str[i]<='9')||str[i]=='X') return 1; } } else return 0; }
#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,n; n=strlen(s); for(i=0;i<=(n/2);++i) { if(s[i]==s[n-i-1]) { return 1; } if(s[i]!=s[n-1-i]) return 0; } }