c++笔试----What will print out？

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.