11. How is fopen()used ?
Ans: The function fopen() returns a file pointer. Hence a file pointer is declared and it is assigned
as
FILE *fp;
fp= fopen(filename,mode);
filename is a string representing the name of the file and the mode represents:
“r” for read operation
“w” for write operation
“a” for append operation
“r+”,”w+”,”a+” for update operation
Ans: The function fopen() returns a file pointer. Hence a file pointer is declared and it is assigned
as
FILE *fp;
fp= fopen(filename,mode);
filename is a string representing the name of the file and the mode represents:
“r” for read operation
“w” for write operation
“a” for append operation
“r+”,”w+”,”a+” for update operation
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12. Differentiate between a constant pointer and pointer to a constant?
Ans:
const char *p; //pointer to a const character.
char const *p; //pointer to a const character.
char * const p; //const pointer to a char variable.
const char * const p; // const pointer to a const character.
Ans:
const char *p; //pointer to a const character.
char const *p; //pointer to a const character.
char * const p; //const pointer to a char variable.
const char * const p; // const pointer to a const character.
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13. Are the expressions *ptr ++ and ++ *ptr same?
Ans: No,*ptr ++ increments pointer and not the value pointed by it. Whereas ++ *ptr
increments the value being pointed to by ptr.
14. What’s the difference between these two declarations?
Ans: struct x1 { … };
typedef struct { … } x2;
The first form declares a structure tag; the second declares a typedef. The main difference is that the second declaration is of a slightly more abstract type.its users don’t necessarily know that it is a structure, and the keyword struct is not used when declaring instances of it.
15. What do the functions atoi(), itoa() and gcvt() do?
Ans:
atoi() is a macro that converts integer to character.
itoa() It converts an integer to string
gcvt() It converts a floating point number to string
16. Can a Structure contain a Pointer to itself?
Ans: Yes such structures are called self-referential structures.
17.Write a program which uses Command Line Arguments?
Ans:
#include
void main(int argc,char *argv[])
{
int i;
clrscr();
for(i=0;i
printf(“\n%d”,argv[i]);
}
18. Difference between syntax vs logical error?
Ans:
Syntax Error
1-These involves validation of syntax of language.
2-compiler prints diagnostic message.
Logical Error
1-logical error are caused by an incorrect algorithm or by a statement mistyped in such a way
that it doesn’t violet syntax of language.
2-difficult to find.
19. What is a preprocessor, what are the advantages of preprocessor?
Ans: A preprocessor processes the source code program before it passes through the compiler.
1- a preprocessor involves the readability of program
2- It facilitates easier modification
3- It helps in writing portable programs
4- It enables easier debugging
5- It enables testing a part of program
6- It helps in developing generalized program
20. what are the types of file?( IMP)
Ans: Files are of two types
1-high level files (stream oriented files) :These files are accessed using library functions
2-low level files(system oriented files) :These files are accessed using system calls
90. Can we use any name in place of argv and argc as command line arguments ?
Ans: yes we can use any user defined name in place of argc and argv;
Ans: No,*ptr ++ increments pointer and not the value pointed by it. Whereas ++ *ptr
increments the value being pointed to by ptr.
14. What’s the difference between these two declarations?
Ans: struct x1 { … };
typedef struct { … } x2;
The first form declares a structure tag; the second declares a typedef. The main difference is that the second declaration is of a slightly more abstract type.its users don’t necessarily know that it is a structure, and the keyword struct is not used when declaring instances of it.
15. What do the functions atoi(), itoa() and gcvt() do?
Ans:
atoi() is a macro that converts integer to character.
itoa() It converts an integer to string
gcvt() It converts a floating point number to string
16. Can a Structure contain a Pointer to itself?
Ans: Yes such structures are called self-referential structures.
17.Write a program which uses Command Line Arguments?
Ans:
#include
void main(int argc,char *argv[])
{
int i;
clrscr();
for(i=0;i
printf(“\n%d”,argv[i]);
}
18. Difference between syntax vs logical error?
Ans:
Syntax Error
1-These involves validation of syntax of language.
2-compiler prints diagnostic message.
Logical Error
1-logical error are caused by an incorrect algorithm or by a statement mistyped in such a way
that it doesn’t violet syntax of language.
2-difficult to find.
19. What is a preprocessor, what are the advantages of preprocessor?
Ans: A preprocessor processes the source code program before it passes through the compiler.
1- a preprocessor involves the readability of program
2- It facilitates easier modification
3- It helps in writing portable programs
4- It enables easier debugging
5- It enables testing a part of program
6- It helps in developing generalized program
20. what are the types of file?( IMP)
Ans: Files are of two types
1-high level files (stream oriented files) :These files are accessed using library functions
2-low level files(system oriented files) :These files are accessed using system calls
90. Can we use any name in place of argv and argc as command line arguments ?
Ans: yes we can use any user defined name in place of argc and argv;
