Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: does any one know how to solve?
Top Forums Programming does any one know how to solve? Post 302228028 by redoubtable on Friday 22nd of August 2008 03:11:08 PM
Old 08-22-2008
Quote:
Originally Posted by shamrock
Imho that solution should be used for both static and dynamic cases. It's not advisable to create a 1000 element array on the stack and end up using only a small portion of it. Knowledge of sizeof operator is even more important if the code was accepting user input from the keyboard because in that scenario calls to malloc() printf() and fgets() have to be interleaved together in order to fill up a single empRec structure though its size should be known beforehand.
I agree with static cases when the total number of structs inside employee is known and sizeof() returns the whole size of the array so if we want to know the number of entries we just have to divide sizeof(employee) for sizeof(struct empRec). But in dynamic cases when the user wishes to add more entries in employee array struct, if the array (employee) is bigger (1000 structs) than the number of entries (struct empRec) it has, sizeof() will not help to determine the number of entries because it will give us the size of those 1000 structs and we just want to know those we're using. Also if pointers/malloc() are used, sizeof() won't be of any help I guess.
Code:
    static struct empRec employee[10] =
    {
        {"Peter North","4B-208",35400,{10,11,1983}},
        {"John Musa","2B-118",25400,{07,10,1993}},
        {"Paula Jeminova","1A-506",18700,{02,1,1990}},
        {"Patricia Silver","6C-123",52100,{14,21,2000}},
        {"Robert mill","4D-318",42100,{01,19,2008}}
    }

In this case, if we would want to add a few more entries dynamically we could not determine the number of existing entries (5) using sizeof(), because sizeof(employee) is the same as saying sizeof(struct empRec)*10.

This is why I was advising the original poster to use a NULL/empty struct reference as the final entry so the number of entries could be calculated by counting structs until an empty one was found.

I also agree that having 1000 entries is far too much, but I was not arguing about that. Anyway, how do you use sizeof() in dynamic cases?
 

6 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

How to solve this

I have to write an script for.. CUST: 123 trans: some contents CUST: 1234 trans: some contents Now wat i have to do is this: CUST:123 akash trans: some contents CUST:1234 akash1 trans: I have been able to add... (3 Replies)
Discussion started by: akashag22
3 Replies

2. Shell Programming and Scripting

Can somebody solve this please

I have to find the files older than 200 days from a path and copy them to some other directory with the current date stamp attached to it. i have written like follows: #!/bin/ksh DSTAMP=$(date +"%y%m%d%H%M") rm $CA_OUT_PATH/ftp_logs/temp touch $CA_OUT_PATH/ftp_logs/temp chmod 777... (1 Reply)
Discussion started by: sreenusola
1 Replies

3. UNIX for Advanced & Expert Users

Can somebody solve this

I have to find the files older than 200 days from a path and copy them to some other directory with the current date stamp attached to it. i have written like follows: #!/bin/ksh DSTAMP=$(date +"%y%m%d%H%M") rm $CA_OUT_PATH/ftp_logs/temp touch $CA_OUT_PATH/ftp_logs/temp chmod 777... (1 Reply)
Discussion started by: sreenusola
1 Replies

4. UNIX for Dummies Questions & Answers

Can somebody solve this

I have to find the files older than 200 days from a path and copy them to some other directory with the current date stamp attached to it. i have written like follows: #!/bin/ksh DSTAMP=$(date +"%y%m%d%H%M") rm $CA_OUT_PATH/ftp_logs/temp touch $CA_OUT_PATH/ftp_logs/temp chmod 777... (13 Replies)
Discussion started by: sreenusola
13 Replies

5. Homework & Coursework Questions

help me to solve it thank you

i thought about to use the commands : wc and sort and mybe more .. i need to write a bash script that recive a list of varuables kaka pele ronaldo beckham zidane messi rivaldo gerrard platini i need the program to print the longest word of the list. word in the output appears on a separate... (1 Reply)
Discussion started by: yairpg
1 Replies

6. UNIX Desktop Questions & Answers

please help me to solve it

i thought about to use the commands : wc and sort cut and mybe more .. i need to write a bash script that recive a list of varuables kaka pele ronaldo beckham zidane messi rivaldo gerrard platini i need the program to print the longest word of the list. word in the output appears on a... (0 Replies)
Discussion started by: yairpg
0 Replies

LEARN ABOUT DEBIAN

ctrsyl

ctrsyl.f(3)							      LAPACK							       ctrsyl.f(3)

NAME

       ctrsyl.f -

SYNOPSIS

   Functions/Subroutines
       subroutine ctrsyl (TRANA, TRANB, ISGN, M, N, A, LDA, B, LDB, C, LDC, SCALE, INFO)
	   CTRSYL

Function/Subroutine Documentation
   subroutine ctrsyl (characterTRANA, characterTRANB, integerISGN, integerM, integerN, complex, dimension( lda, * )A, integerLDA, complex,
       dimension( ldb, * )B, integerLDB, complex, dimension( ldc, * )C, integerLDC, realSCALE, integerINFO)
       CTRSYL

       Purpose:

	    CTRSYL solves the complex Sylvester matrix equation:

	       op(A)*X + X*op(B) = scale*C or
	       op(A)*X - X*op(B) = scale*C,

	    where op(A) = A or A**H, and A and B are both upper triangular. A is
	    M-by-M and B is N-by-N; the right hand side C and the solution X are
	    M-by-N; and scale is an output scale factor, set <= 1 to avoid
	    overflow in X.

       Parameters:
	   TRANA

		     TRANA is CHARACTER*1
		     Specifies the option op(A):
		     = 'N': op(A) = A	 (No transpose)
		     = 'C': op(A) = A**H (Conjugate transpose)

	   TRANB

		     TRANB is CHARACTER*1
		     Specifies the option op(B):
		     = 'N': op(B) = B	 (No transpose)
		     = 'C': op(B) = B**H (Conjugate transpose)

	   ISGN

		     ISGN is INTEGER
		     Specifies the sign in the equation:
		     = +1: solve op(A)*X + X*op(B) = scale*C
		     = -1: solve op(A)*X - X*op(B) = scale*C

	   M

		     M is INTEGER
		     The order of the matrix A, and the number of rows in the
		     matrices X and C. M >= 0.

	   N

		     N is INTEGER
		     The order of the matrix B, and the number of columns in the
		     matrices X and C. N >= 0.

	   A

		     A is COMPLEX array, dimension (LDA,M)
		     The upper triangular matrix A.

	   LDA

		     LDA is INTEGER
		     The leading dimension of the array A. LDA >= max(1,M).

	   B

		     B is COMPLEX array, dimension (LDB,N)
		     The upper triangular matrix B.

	   LDB

		     LDB is INTEGER
		     The leading dimension of the array B. LDB >= max(1,N).

	   C

		     C is COMPLEX array, dimension (LDC,N)
		     On entry, the M-by-N right hand side matrix C.
		     On exit, C is overwritten by the solution matrix X.

	   LDC

		     LDC is INTEGER
		     The leading dimension of the array C. LDC >= max(1,M)

	   SCALE

		     SCALE is REAL
		     The scale factor, scale, set <= 1 to avoid overflow in X.

	   INFO

		     INFO is INTEGER
		     = 0: successful exit
		     < 0: if INFO = -i, the i-th argument had an illegal value
		     = 1: A and B have common or very close eigenvalues; perturbed
			  values were used to solve the equation (but the matrices
			  A and B are unchanged).

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   November 2011

       Definition at line 157 of file ctrsyl.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

Version 3.4.1							  Sun May 26 2013						       ctrsyl.f(3)
All times are GMT -4. The time now is 03:35 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy