Looking for spaces in a string of chars.

This is a discussion on Looking for spaces in a string of chars. within the C++ Programming forums, part of the General Programming Boards category; I am trying to to get this program to find spaces in a string of characters and display the count. ...

  1. #1
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    Question Looking for spaces in a string of chars.

    I am trying to to get this program to find spaces in a
    string of characters and display the count.
    I am not sure of my codes and the error that I got seems
    a little strange. Can anyone look at my codes and give me
    some pointers.
    Thank you
    My os is VC++ ver. 6.0, I have a desktop using win 2k.
    =================
    My codes and the returned errors.
    +++++++++++++++++++++++++++


    #include <iostream>
    #include <cstring>
    using namespace std;

    // not used --->char locate_blank(char *);

    char line[] = "This is a string test. It contains two sentence.";

    int main()
    {
    int count;
    cout << "The original sentence is : " << line;

    for (count = 0; line[count]= '\0'; count++)
    {
    if (line[count] == ' ')
    {
    line[count+1] = ' ';
    break;
    }
    return count;
    }
    cout << "This sentence contains" << count(line) << "blanks";
    }

    /* Error list
    ------Configuration: findBlanks#2 - Win32 Debug-------
    Compiling...
    findBlanks#2.cpp
    C:\Documents\Desktop\findBlanks#2.cpp(23) : error C2064: term does not evaluate to a function
    Error executing cl.exe.

    findBlanks#2.obj - 1 error(s), 0 warning(s)

  2. #2
    Confused Magos's Avatar
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    reply

    for (count = 0; line[count]= '\0'; count++)

    This seem a little strange. You set all elements to NULL. It should be line[count] != '/0' if I understand it right. Or why not do this:
    for(count=0; count<strlen(line); count++)
    (strlen calculates the length of a string)
    MagosX.com

    Give a man a fish and you feed him for a day.
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  3. #3
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    Counting is as simple as calling std::count:
    Code:
    #include <iostream>
    #include <algorithm>
    
    // Returns how many elements an array has.
    template<class T> inline size_t elems(const T& array) {
        return sizeof array / sizeof *array;
    }
    
    int main() {
        char line[] = "Hello world! This sentence contains some blanks.";
    
        // You call cout with a range and a value to count.
        // So std::count(line, line + elems(line), ' ') will count
        // all ' ' in the range [line; line + elems(line))
        std::cout << line << "\nThe above line conains "
            << std::count(line, line + elems(line), ' ') << " blanks.";
    }
    - lmov

  4. #4
    Unregistered
    Guest
    Hello,

    Could you explain

    ----------------------

    // Returns how many elements an array has.
    template<class T> inline size_t elems(const T& array) {
    return sizeof array / sizeof *array;
    }

    ---------------------

    A little more in detail for me? I have been taking classes for about 2 years and I haven't seen this used before, and it looks like a nice piece of code.

    Btw, im not the one who started this thread, just curious.

  5. #5
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    Guest
    Imov has a compiler that is compliant in use of namespaces and the standard template library. Unfortunately, many of us do not. Therefore we can not make use of functions present in STL llike count().

    The good news is that even many of the older compilers do allow templates. Templates allow you to postpone declaring the actual type of a variable to be used in a function or a class until run time. As long as the class has all the necessary functionality for the template to work it will be useable. This allows you more flexibility and reuseability when writing code. To indicate use of templates you need to use the key word template and then enclose the name of the template variable(s) you are going to allow in angled brackets. Then you can write out the code using the template class whereever indicated. In this case the function will calculate the number of elements in an array using the sizeof operator by calculating the size of the whole array and dividing it by the size of the first element in the array. The return type of the function is in size_t which is a "fancy" way of saying type int since not all systems use the same memory pattern for type int, some use 16 bit ints and some 32 bit ints. Inline is another keyword that means the compiler has a variety of options as to how it wishes to deal with this function in order to tweak as much performance from the function as possible. You should never inline large functions as you are likely to defeat the purpose of inlining in the first place. Many people seldom use this syntax, but it is something you should know a little about anyway.

    if you have an older compiler and you don't want to get fancy you could do this:

    for(int i = 0; i < strlen(line); i++)
    {
    if(line[i] == ' ')
    count++;
    }
    }

    In fact that should work anywhere, but it's not as sophisticated as the code in Imov's post.

  6. #6
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    Imov has a compiler that is compliant in use of namespaces and the standard template library. Unfortunately, many of us do not.
    GCC, one of the best compilers I've seen, is available free for download at http://gcc.gnu.org. The Windows version is available at http://www.mingw.org. You can also get a free IDE at http://www.bloodshed.net.
    Last edited by lmov; 01-26-2002 at 12:06 PM.
    - lmov

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