C-language 56 programming Questions

                                                                     

    C-language 56 programming Questions                                                                
                                                                     
1.

#include<stdio.h>
void main()
{
 int arr[];
 arr[1]=10;
 printf("%d",arr[0]);
}

2.

#include<stdio.h>
void main()
{
 int arr[2]={10,20,30,40};
 printf("%d",*(arr+2));
}

3.

#include<stdio.h>
void main()
{

 int arr[2]={10,20};
 arr[2]=30;
 arr[3]3=40;
 printf("%d",*(arr+3));
}

4.

#include<stdio.h>
void main()
{
 int arr[2]={10,20};
 *arr=30;
 *(arr+1)=40;
 printf("%d%d",arr[0],1[arr]);
}

5.

#include<stdio.h>
void main()
{
 int a=1;
 void xyz(int,int);
 xyz(++a,a++);
 xyz(a++,++a);
 printf("\n%d",a);
}

void xyz(int x,int y)
{
 printf("\n%d%d",x,y);
}

6.

#include<stdio.h>
void abc()
{
 ++a;
}
void main()
{
 int a=1;
 abc();
 printf("\n %d",a);
}

7.

void display(int a)
{
 printf("\n %d",a);
 if(--a)
  display(a);
 printf("\n%d",a);
}

void main()
{
 display(4);
}

8.

void xyz(int x)
{
 printf("\n%d",x);
 if(x)
  xyz(x-1);
 printf("\n%d",x);
}
void abc(int a)
{
 printf("\n%d",a);
 xyz(a);
 if(a)
  abc(a-1);
 printf("\n%d",a);
}

void main()
{
 abc(2);
}

9.
#include<stdio.h>
void main()
{

 static int a=1;
 printf("\n%d",++a);
 if(a<=3)
  main();
 printf("\n%d",a);
}

10.

#include<stdio.h>
void main()
{
 int a=32767,b;
 char *ptr;
 ptr=&a;
 b=*ptr;
 printf("\n%d%d",a,b);
}

11.

#include<stdio.h>
void main()
{
 int a=10;
 int *p=&a;
 int **pp=&p;
 ++*p;
 ++**pp;
 a*=a-2;
 printf("\n%d",*a);
}

12.

void change(int p1,int *p2)
{
 ++p1;
 ++*p2;
}

void main()
{
 int x=10,y=20;
 change(x,&y);
 printf("\n%d%d",x,y);
}


13.
#include<stdio.h>
void main()
{
 int a[]=[7,18,29};
 int *p;
 p=a;
 ++p;
 printf("%d%d%d",p[-1],p[0],p[1]);
}

14.

void xyz(int *ptr)
{
 ++*ptr;
 if(*ptr<=10)
  xyz(++ptr);
 ++*ptr;
}
void main()
{
 int arr[]={2,4,8,14,16};
 int i;
 xyz(arr+1);
 for(i=0;i<5;i++)
  printf("%d",arr[i]);
}

15.

#include<stdio.h>
void main()
{

 int arr[4][8]={10,20,30};
 printf("\n%d",sizeof(arr));
 printf("\n%d",sizeof(arr[1]));
 printf("\n%d",sizeof(arr[1][0]);
}

16.

#include<stdio.h>
void main()
{
 int arr[4][8]={10,20,30};
 printf("\n%d",&arr[3][4]-&arr[1][2]);
}

17.

#include<stdio.h>
void main()
{
 int arr[3][]={
   {7,8,9},
   {3,13},
   {10,20,30}
   };
 printf("\n%d",arr[1][1]);
}

18.

#include<stdio.h>
void main()
{ 
 int arr[][4]={
   {7,8,9},
   {3,13},
   {10,20,30}
   };
 printf("\n%d",arr[1][1]);
}

19.

#include<stdio.h>
void main()
{

 int arr[5]={10,20};
 printf("\n%d%d",1[arr],arr[0]);
}

20.

#include<stdio.h>
void main()
{

 int arr1[5]={10,20};
 int arr2[5];
 printf("\n%d%d",arr1[3],arr2[3]);
}


21.

#include<stdio.h>
void main()
{

 int a[2];
 int i;
 for(i=0;i<10;i++)
  a[i]=i*i;
 printf("%d%d",a[3],a[4]);

}

22.

#include<stdio.h>
void main()
{

 int a[5]={10,20,30,40,50};
 int b[5]={3,13};
 b=a;
 printf("%d",b[1]);
} 

23.

#include<stdio.h>
void main()
{


 int a[5]={6,16,26};
 ++*a;
 ++*(a+1);
 ++a[1];
 printf("%d%d",a[0],a[1]);
}

24.

#include<stdio.h>
void main()
{


 int a[5]={10,20,30,40,50};
 int *ptr;
 ptr=a+1;
 printf("%d%d%d",++*ptr,*ptr++,*++ptr);
}

25.

#include<stdio.h>
void main()
{

 char str[5]={'a','b','c','d'};
 printf("%s",str);

}

26.

#include<stdio.h>
void main()
{

 char str[]="abcdefghxyz";
 printf("\n%s",str);
 printf("\n%s",str+4);
 printf("\n%s",str+8);

}

27.

#include<stdio.h>
void main()
{

 char str[]="Naresh IT";
 str[1]++;
 str[2]=100;
 puts(str);
}

28.

#include<stdio.h>
void main()
{

 char str[]="abcdef";
 str[3]=0;
 puts(str);
}

29.

#include<stdio.h>
void main()
{
 char str1[]="hello";
 char str2[]="abc";
 str1=str2;
 puts(str1);

}

30.

void display(char *str)
{
 puts(str)
 if(*str)
  display(str+1);
 puts(str);
}

void main()
{
 char st[]="abc";
 display(st);
}

31.

#include<stdio.h>
void main()
{
 char str="abcdef";
 ++str;
 ++*str;
 puts(str);
}


32.

void main()
{
 char str[]="Balu";
 printf("%d%d",sizeof(str),strlen(str));
}

33.

#include<stdio.h>
void main()
{

 char str1[20]= "hello Naresh IT";
 char str2[20]="hello Balu";
 strcpy(str1+6,str2+6);
 puts(str1);
 puts(str2);
}

34.

char *change(char *ptr)
{
 ++*ptr;
 ++[tr;
 ptr+=2;
 *ptr+=2;
 return ptr-2;
}

void main()
{
 char name[]="hello rahul";
 puts(change(name));
 puts(name);
}


35.

#include<stdio.h>
void main()
{

 char str[40]="welcome";
 char *p;
 p=str+7;
 strcpy(p,"balu");
 puts(p);
 puts(str);
}

36.

#include<stdio.h>
void main()
{

 char s1[40]="abcdef";
 char *s2="Naresh IT";
 char *s3="Balu";
 s3=s2+2;
 s2=s1+2;
 ++*s2;
 ++*s3;
 puts(s1);
 puts(s2);
 puts(s3);
}

37.

#include<stdio.h>
void main()
{
 char str[40]="abc789101112";
 strrev(str+3);
 puts(str);

}


38.

#include<stdio.h>
void main()
{

 char s1[40]="abcdf";
 char s2[]="xyz";
 strcat(s1+2,s2+1);
 puts(s1);
 puts(s2);
}

39.
void dump(char *p1,char *p2)
{
 while(*p1++=*p2++);
}
void main()
{
 char str1[]="hello Naresh IT";
 char str2[]="Balu";
 dump(str1,str2);
 puts(str1);
 puts(str2);
}

40.

#include<stdio.h>
void main()
{

 char s[4][40]={"abc","123","xyz"};
 char *p[4]={"pascal","cobol"};
 printf("\n%d",sizeof(s));
 printf("\n%d",sizeof(p));
}

41.
#include<stdio.h>
void main()
{
 char str[2]="hello";
 puts(str);

}

42.
#include<stdio.h>
void main()
{

 char str[2];
 strcpy(str,"hello");
 puts(str);

}


43.

#define cube(x) (x*x*x)
void main()
{

 int a;
 a=cube(2);
 printf("%d",a)'
 a=cube(2+3);
 printf("%d",a);
}

44.

#define A 10
void main()
{
 int x;
 x=++A;
 printf("%d%d",x,A);
}


45.

enum{a,b,c=10,d};
void main()
{
 printf("\n %d%d%d",a,b,c,d);
}

46.

struct a
{
 int x,y,z;
}a1;
void main()
{
 printf("%d",sizeof(a1));
}

47.

struct B
{
 struct 
 {
  int x;
  int y;
  int z;
 }obj1,obj2;
 int a;
 int b;
}b1;

void main()
{
 printf("%d",sizeof(b1));
}


48.
for above struct B variable b1 how to interact with member x...?

49.

union a
{
 int a;
 char c;
}obj;
void main()
{
 obj.a=511;
 printf("%d%d",obj.a,obj.c);
 obj.c=1;
 printf("%d%d",obj.a,obj.c);
}

50.

typedef struct
{
 int d;
 char na[30];
 int sal;
}emp;

void main()
{
 emp e1;
 emp *ptr;
 ptr=&e1;
 ...
 ...
}

in the above object e1 need to change name to "Naresh IT" which are valid
1.e1.na="Naresh IT";
2.atrcpy(e1.na,"Naresh IT");
3.ptr->na="Naresh IT";
4.strcpy(ptr->na,"Naresh IT");

51.

for the same object e1 need to change id to 1 which are valid.

1.e1.id=1;
2.e1->id=1;
3.ptr.id=1;
4.*ptr.id=1;
5.ptr->id=1;

52.

fopen required how many arguments?

53.
what are the differences between malloc and calloc
1. malloc has 2 args calloc has 1 args
2.malloc all bytes are garbage.calloc all bytes are zeros
3.calloc all bytes are garbage.malloc all bits are zeros.
4.malloc has 1 args and calloc has 2 args.

54.

if malloc fails what it returns?

55.

what is the default value of argc--,argv[0]--?

56.
what is __argc,__argv and where it is defined?