C interview questions part1

C interview questions part1

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.

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