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應(yīng)屆大學(xué)生面試技巧嵌入式方面（3）
作為一個即將畢業(yè)的大學(xué)生，在外地實習(xí)找工作確實是一件很痛苦的事情，我們沒有很強(qiáng)的技能（除過那些很BT的家伙）,沒有一定的社會閱歷,甚至沒有一點家庭背景.但是作為企業(yè)來說,他們在很大程度上也都是很了解應(yīng)屆大學(xué)生的,他們對我們的要求不是很高,除非有的公司是想刁難你,但是這樣的事情是很少發(fā)生的,
我就我在北京的一些找工作的經(jīng)驗和學(xué)習(xí)到的一些知識分享給大家,僅代表一家之言,不足之處請大家指正.
操作篇：發(fā)些代碼給大家做做筆試參考.
1.下面的代碼輸出是什么，為什么？
void foo(void)
{ unsigned int a = 6;
int b = -20;
(a+b > 6) puts("> 6") : puts("<= 6");
}
2.評價下面的代碼片斷：
unsigned int zero = 0;
unsigned int compzero = 0xFFFF;
對于一個int型不是16位的處理器為說，上面的代碼是不正確的。應(yīng)編寫如下：
unsigned int compzero = ~0;
3.求輸出char *ptr;
if ((ptr = (char *)malloc(0)) == NULL)
puts("Got a null pointer");
else
puts("Got a valid pointer");
4.C語言同意一些令人震驚的結(jié)構(gòu),下面的結(jié)構(gòu)是合法的嗎，如果是它做些什么？
int a = 5, b = 7, c;
c = a+++b;
5.What will print out?
main()
{ char *p1=“name”;
char *p2;
p2=(char*)malloc(20);
memset (p2, 0, 20);
while(*p2++ = *p1++);
printf(“%sn”,p2);
}
Answer:empty string.
What will be printed as the result of the operation below:
main()
{ int x=20,y=35;
x=y++ + x++;
y= ++y + ++x;
printf(“%d%dn”,x,y);
}
Answer : 5794
What will be printed as the result of the operation below:
main()
{ int x=5;
printf(“%d,%d,%dn”,x,x<<2,x>>2);
}
Answer: 5,20,1
What will be printed as the result of the operation below:
#define swap(a,b) a=a+b;b=a-b;a=a-b;
void main()
{ int x=5, y=10;
swap (x,y);
printf(“%d %dn”,x,y);
swap2(x,y);
printf(“%d %dn”,x,y);
}
int swap2(int a, int b)
{ int temp;
temp=a;
b=a;
a=temp;
return 0;
}
Answer: 10, 5
10, 5
What will be printed as the result of the operation below:
main()
{ char *ptr = ” Cisco Systems”;
*ptr++; printf(“%sn”,ptr);
ptr++;
printf(“%sn”,ptr);
}
Answer:Cisco Systems
isco systems
What will be printed as the result of the operation below:
main()
{ char s1[]=“Cisco”;
char s2[]= “systems”;
printf(“%s”,s1);
} Answer: Cisco
What will be printed as the result of the operation below:
main()
{ char *p1;
char *p2;
p1=(char *)malloc(25);
p2=(char *)malloc(25);
strcpy(p1,”Cisco”);
strcpy(p2,“systems”);
strcat(p1,p2);
printf(“%s”,p1);
}
Answer: Ciscosystems
The following variable is available in file1.c, who can access it?:
static int average;
Answer: all the functions in the file1.c can access the variable.
WHat will be the result of the following code?
#define TRUE 0 // some code
while(TRUE)
{
// some code
}
Answer: This will not go into the loop as TRUE is defined as 0.
What will be printed as the result of the operation below:
int x;
int modifyvalue()
{ return(x+=10);
} int changevalue(int x)
{ return(x+=1);
}
void main()
{ int x=10;
x++;
changevalue(x);
x++;
modifyvalue();
printf("First output:%dn",x);
x++;
changevalue(x);
printf("Second output:%dn",x);
modifyvalue();
printf("Third output:%dn",x);
}
Answer: 12 , 13 , 13
What will be printed as the result of the operation below:
main()
{ int x=10, y=15;
x = x++;
y = ++y;
printf(“%d %dn”,x,y);
}
Answer: 11, 16
What will be printed as the result of the operation below:
main()
{ int a=0;
if(a==0)
printf(“Cisco Systemsn”);
printf(“Cisco Systemsn”);
}
Answer: Two lines with “Cisco Systems” will be printed.
再次更新C++相關(guān)題集
6. 以下三條輸出語句分別輸出什么？[C易]
char str1[] = "abc";
char str2[] = "abc";
const char str3[] = "abc";
const char str4[] = "abc";
const char* str5 = "abc";
const char* str6 = "abc";
cout << boolalpha << ( str1==str2 ) << endl; // 輸出什么？ 0
cout << boolalpha << ( str3==str4 ) << endl; // 輸出什么？ 0
cout << boolalpha << ( str5==str6 ) << endl; // 輸出什么？ 1
7.寫一個函數(shù)，反映出電腦是大端存儲（BIG_ENDER）還是小端存儲(LITTLE_ENDER)?
8.不用庫函數(shù)，編寫函數(shù)strcmp()和strcat() strcpy()
9.折半查找函數(shù)？
10.int fun(int *p）和int fun(int p)區(qū)別？
11.struct
{
bit a;
char b;
int c;
float d;
}a;
求sizeof(a)=?
12.int main(int argc,char *argv[])
{
int c=9,d=0;
c=c++%5;
d=c;
printf("d=%d\n",d);
return 0;
}
a) 寫出程序輸出
5
b) 在一個可移植的系統(tǒng)中這種表達(dá)式是否存在風(fēng)險？why?
13 .# include "stdio.h"
int a=0;
int b;
static char c;
int main(int argc,char *argv[])
{
char d=4;
static short e;
a++;
b=100;
c=(char)++a;
e=(++d)++;
printf("a=%d, b=%d, c=%d, d= %d, e=%d",a,b,c,d,e);
return 0;
}
a) 寫出程序輸出
以前學(xué)過c++,這個是可以的 e=(++d)++;
現(xiàn)在才發(fā)現(xiàn)在c中，這是不行的
a=2, b=100, c=2, d= 6, e=5
b) 編譯器如果安排各個變量(a,b,c,d)在內(nèi)存中的布局(eg. stack,heap,data section,bss section),最好用圖形方式描述。
data section: a
bss section: b,c,e
stack d
在采用段式內(nèi)存管理的架構(gòu)中，數(shù)據(jù)段（data segment）通常是指用來存放程序中已初始化的全局變量的一塊內(nèi)存區(qū)域。數(shù)據(jù)段屬于靜態(tài)內(nèi)存分配。
在采用段式內(nèi)存管理的架構(gòu)中，BSS段（bss segment）通常是指用來存放程序中未初始化的全局變量的一塊內(nèi)存區(qū)域。BSS是英文Block Started by Symbol的簡稱。BSS段屬于靜態(tài)內(nèi)存分配。