C Programming Job Interview Questions

1. What will print out?

   main()
   {
   char *p1=“name”;
   char *p2;
   p2=(char*)malloc(20);
   memset (p2, 0, 20);
   while(*p2++ = *p1++);
   printf(“%s\n”,p2);

   }

   Answer:empty string.

2. 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%d\n”,x,y);

   }

   Answer : 5794

3. What will be printed as the result of the operation below:
   

   main()
   {
   int x=5;
   printf(“%d,%d,%d\n”,x,x< <2,x>>2);

   }

   Answer: 5,20,1

4. 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 %d\n”,x,y);
   swap2(x,y);
   printf(“%d %d\n”,x,y);
   }

   int swap2(int a, int b)
   {
   int temp;
   temp=a;
   b=a;
   a=temp;
   return 0;

   }

   Answer: 10, 5
   10, 5

5. What will be printed as the result of the operation below:
   

   main()
   {
   char *ptr = ” Cisco Systems”;
   *ptr++; printf(“%s\n”,ptr);
   ptr++;
   printf(“%s\n”,ptr);

   }

   Answer:Cisco Systems
   isco systems

6. What will be printed as the result of the operation below:
   

   main()
   {
   char s1[]=“Cisco”;
   char s2[]= “systems”;
   printf(“%s”,s1);
   }

   Answer: Cisco

7. 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

8. 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.

9. 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.

10. 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:%d\n",x);

    x++;
    changevalue(x);
    printf("Second output:%d\n",x);
    modifyvalue();
    printf("Third output:%d\n",x);

    }

    Answer: 12 , 13 , 13

11. What will be printed as the result of the operation below:
    

    main()
    {
    int x=10, y=15;
    x = x++;
    y = ++y;
    printf(“%d %d\n”,x,y);

    }

    Answer: 11, 16

12. What will be printed as the result of the operation below:
    

    main()
    {
    int a=0;
    if(a==0)
    printf(“Cisco Systems\n”);
    printf(“Cisco Systems\n”);

    }

    Answer: Two lines with “Cisco Systems” will be printed.