c language interview questions | Part9

If you would like to view All C language interview questions only at one place visit below link All C Language Interview Questions 81. What is a file pointer? Ans: The pointer to a FILE data type is called as a stream pointer or a file pointer. A file pointer points to the block of information of the stream that had just been opened. 82. 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 83How is a file closed ? Ans: A file is closed using fclose() function Eg. fclose(fp); Where fp is a file pointer. 84. What is a random access file? Ans: A file can be accessed at random using fseek() function fseek(fp,position,origin); fp file pointer position number of bytes offset from origin origin 0,1 or 2 denote the beginning ,current position or end of file respectively. 85. What is the purpose of ftell ? Ans: The function ftell() is used to get the current file represented by the file pointer. ftell(fp); returns a long integer value representing the current file position of the file pointed by the file pointer fp.If an error occurs ,-1 is returned. 86. What is the purpose of rewind() ? Ans: The function rewind is used to bring the file pointer to the beginning of the file. Rewind(fp); Where fp is a file pointer.Also we can get the same effect by feek(fp,0,0); 87. Difference between a array name and a pointer variable? Ans: A pointer variable is a variable where as an array name is a fixed address and is not a variable. A pointer variable must be initialized but an array name cannot be initialized. An array name being a constant value , ++ and — operators cannot be applied to it. 88. Represent a two-dimensional array using pointer? Ans: Address of a[I][j] Value of a[I][j] &a[I][j] or a[I] + j or *(a+I) + j *&a[I][j] or a[I][j] or *(a[I] + j ) or *( * ( a+I) +j ) 89. Difference between an array of pointers and a pointer to an array? Ans: Array of pointers 1- Declaration is: data_type *array_name[size]; 2-Size represents the row size. 3- The space for columns may be dynamically Pointers to an array 1-Declaration is data_type ( *array_name)[size]; 2-Size represents the column size. 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; Related Fresher Interview Questions 1. C Language Interview Questions
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