嵌入式相关笔试题目汇总

嵌入式相关笔试题目汇总

1、将一个字符串逆序

#include <iostream>using namespace std;//#define NULL ((void *)0)char * mystrrev(char * const dest,const char * const src){if (dest==NULL && src==NULL) return NULL;char *addr = dest;int val_len = strlen(src);dest[val_len] = '/0';int i;for (i=0; i<val_len; i++){ *(dest+i) = *(src+val_len-i-1); }return addr;}main(){char *str="asdfa";char *str1=NULL;str1 = (char *)malloc(20);if (str1 == NULL) cout<<"malloc failed";cout<<mystrrev(str1,str);free(str1);str1=NULL;//杜绝野指针}  
2、将一个链表逆序

#include <stdio.h> #include <ctype.h> #include <stdlib.h> typedef struct List{ int data; struct List *next; }List; List *list_create(void) { struct List *head,*tail,*p; int e; head=(List *)malloc(sizeof(List)); tail=head; printf("/nList Create,input numbers(end of 0):"); scanf("%d",&e); while(e){ p=(List *)malloc(sizeof(List)); p->data=e; tail->next=p; tail=p; scanf("%d",&e);} tail->next=NULL; return head; } List *list_reverse(List *head)//核心代码 { List *p,*q,*r; p=head; q=p->next; while(q!=NULL) { r=q->next; q->next=p; p=q; q=r; } head->next=NULL; head=p; return head; } void main(void) { struct List *head,*p; int d; head=list_create(); printf("/n"); for(p=head->next;p;p=p->next) printf("--%d--",p->data); head=list_reverse(head); printf("/n"); for(p=head;p->next;p=p->next) printf("--%d--",p->data); }
3、计算一个字节里（byte）里面有多少bit被置1

#incluede<iostream>#define N 10//定义BYTE类型别名#ifndef BYTEtypedef unsigned char BYTE;#endifint comb(BYTE b[],int n){int count=0;int bi,bj;BYTE cc=1,tt;//历遍到第bi个BYTE数据for(bi=0;bi<n;bi++){//计算该BYTE的8个bit中有多少个1tt=b[bi]; for(bj=0;bj<8;bj++){ //与1相与或模2结果是否是1？测试当前bit是否为1 //if(tt%2==1) if((tt&cc)==1){ count++; } //右移一位或除以2，效果相同//tt=tt>>1;tt=tt/2;}}return count;}//测试int main(){BYTE b[10]={3,3,3,11,1,1,1,1,1,1};cout<<comb(b,N)<<endl;return 0;}
4、搜索给定的字节(byte)
5、在一个字符串中找到可能的最长的子字符串

char * search(char *cpSource, char ch){char *cpTemp=NULL, *cpDest=NULL;int iTemp, iCount=0;while(*cpSource){if(*cpSource == ch){iTemp = 0;cpTemp = cpSource;while(*cpSource == ch) ++iTemp, ++cpSource;if(iTemp > iCount) iCount = iTemp, cpDest = cpTemp;if(!*cpSource) break;}++cpSource;}return cpDest;}
6、字符串转换为整数

int MyAtoI(char str[]){int i;int weight = 1; // 权重int rtn = 0; // 用作返回for(i = strlen(str) - 1; i >= 0; i--){ rtn += (str[i] - '0')* weight; // weight *= 10; // 增重}return rtn;}void main(){char str[32];printf("Input a string :");gets(str);printf("%d/n", MyAtoI(str));}
7、整数转换为字符串

#include<stdio.h>#include<string.h>void reverse(char s[]) { //字符串反转 int c, i=0, j; for(j=strlen(s)-1;i<j;j--) { c=s[i]; s[i]=s[j]; s[j]=c; i++; } }void IntegerToString(char s[],int n) { int i=0,sign; if((sign=n)<0)//如果是负数，先转成正数 n=-n; do //从个位开始变成字符,直到最高位,最后应该反转 { s[i++]=n%10+'0'; }while((n=n/10)>0); //如果是负数，补上负号 if(sign<0) s[i++]='-'; s[i]='/0';//字符串结束 reverse(s); } void main(){ int m; char c[100]; printf("请输入整数m: "); scanf("%d",&m); IntegerToString(c,m); printf("integer = %d string = %s/n", m, c);}