Coverting a string into upper or lowercase

This is a discussion on Coverting a string into upper or lowercase within the C++ Programming forums, part of the General Programming Boards category; Need some help with a program I am rying to work. I am trying to have a user input a ...

  1. #1
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    Coverting a string into upper or lowercase

    Need some help with a program I am rying to work.

    I am trying to have a user input a string of characters, then count and compare the number of upper and lower case characters, then gie the option to change the string to all upper or all lower case letters, then display the changed string on the screen.


    Code:
    #include <iostream>
    #include <string>
    using namespace std;
    
    int main()
    {
           string x = "";
    	cout<<"Type your string: ";
    	cin>>x;
    
         return 0;
    
    }
    I have been completely stuck on this for the past 2 days.

    I was told by a friend that I needed to use ascii somehow? how?

  2. #2
    Registered User slaveofthenet's Avatar
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    Use the functions isupper(), islower(), toupper(), and tolower() from ctype.h. They all accept a single character as a parameter.
    Detailed understanding of language features - even of all features of a language - cannot compensate for lack of an overall view of the language and the fundamental techniques for using it. - Bjarne Stroustrup

  3. #3
    Confused
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    I believe that if you use (char) in the toupper and tolower functions, you can input a string of text, too.

  4. #4
    Registered User slaveofthenet's Avatar
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    You can go toupper(97) that's the same as toupper('a') because 'a' is the ascii value of 97. http://www.asciitable.com/ for a decent ascii reference.
    Detailed understanding of language features - even of all features of a language - cannot compensate for lack of an overall view of the language and the fundamental techniques for using it. - Bjarne Stroustrup

  5. #5
    Confused
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    Yes, but you can also do something like :

    Code:
    cout << (char)toupper((char)"hello");

    That's not right I think, but it's something like this, I tried it a few days ago.

  6. #6
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    Code:
    #include <iostream>
    #include <string>
    #include <algorithm>
    #include <functional>
    
    using namespace std;
    
    int main()
    {
       string str = "Hello World";
    
       transform(str.begin(),str.end(),str.begin(),ptr_fun(toupper));
    
       cout << str << endl;
    }

  7. #7
    End Of Line Hammer's Avatar
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    When all else fails, read the instructions.
    If you're posting code, use code tags: [code] /* insert code here */ [/code]

  8. #8
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    Smile

    This works with Borland and MS Visual C
    Code:
    #include <iostream.h>
    #include <string.h>
    #include <conio.h>
    
    int main()
    {   
        char* x ;
        int ucase=0;
        int lcase=0;
    	cout<<"Type your string: ";
    	cin.getline( x,100);
    	           
    	for(int i=0;i<strlen(x);i++)
    		{
    			if((x[i]>90)&&!(x[i]==32))
    				{
    		 		x[i]=x[i]-32;
    		        lcase++;
    		    	}
    		  	if(x[i]==32)ucase--;
    	     }
    	   
    	 ucase =strlen(x)-lcase+ucase; 
    	
    	 cout<<"The string you entered in uppercase was "<< x<<endl;
    	 cout<<"There were "<<ucase<<" uppercase letters in the string"<<endl;
    	 cout<<"There were "<<lcase<<" lowercase letters in the string"<<endl;
         getch();
         return 0;

  9. #9
    Registered User slaveofthenet's Avatar
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    bigwullie, you can use the ascii values instead of their decimal equivalents, ie:
    Code:
    char c;
    ...
    if (c >= 'a' && c <= 'z') // c is lowercase
    if (c >= 'A' && c <= 'Z') // c is uppercase
    else // c is not a letter
    It's also better to use <iostream> and <string> over their deprecated counterparts. You should also check out strings and why they are often preferred over char pointers.
    Detailed understanding of language features - even of all features of a language - cannot compensate for lack of an overall view of the language and the fundamental techniques for using it. - Bjarne Stroustrup

  10. #10
    I lurk
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    Originally posted by bigwullie
    This works with Borland and MS Visual C
    Code:
    #include <iostream.h>
    #include <string.h>
    #include <conio.h>
    
    int main()
    {   
        char* x ;
        int ucase=0;
        int lcase=0;
    	cout<<"Type your string: ";
    	cin.getline( x,100);
    	           
    	for(int i=0;i<strlen(x);i++)
    		{
    			if((x[i]>90)&&!(x[i]==32))
    				{
    		 		x[i]=x[i]-32;
    		        lcase++;
    		    	}
    		  	if(x[i]==32)ucase--;
    	     }
    	   
    	 ucase =strlen(x)-lcase+ucase; 
    	
    	 cout<<"The string you entered in uppercase was "<< x<<endl;
    	 cout<<"There were "<<ucase<<" uppercase letters in the string"<<endl;
    	 cout<<"There were "<<lcase<<" lowercase letters in the string"<<endl;
         getch();
         return 0;
    I'm suprised you didn't write your own strlen/output routine.

  11. #11
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    that helped, one more thing

    Ok I got the string to switch to upper or lower case, now what I need to do is insert a conditional statement asking if the user wants to change the case of the string after it reports the number of upper vs. lower case letters.

    [code]

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

    using std::cout;
    using std::endl;

    int main(void)
    {
    char sent[] = "";
    char* x=0;
    int ucase=0;
    int lcase=0;
    cout << "Input Your String: " << sent << endl;
    cin>> sent;

    for(int i=0;i<strlen(sent);i++){

    if((sent[i]>90)&&!(sent[i]==32)){
    sent[i]=sent[i]-32;
    lcase++;
    }
    if(sent[i]==32)ucase--;
    }

    ucase =strlen(sent)-lcase+ucase;

    cout<<"There were "<<ucase<<" uppercase letters in the string"<<endl;
    cout<<"There were "<<lcase<<" lowercase letters in the string"<<endl;
    cout<<"Change the case of the string? (Y or N)" <<endl;

    // does the conditional statemnt go here? or before the cout above?

    for (char *iter = sent; *iter != '\0'; ++iter)
    {
    *iter = tolower(*iter);
    ++iter;
    }

    cout << "Here is your converted string: " << sent << endl;

    return 0;
    }

  12. #12
    Registered User slaveofthenet's Avatar
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    You started out on the right foot using string, I'm not quite sure why you reverted to using character arrays and not using functions which are already provided for you in cctype.
    Code:
    string s;
    int upper = 0, lower = 0;
    char c;
    cin >> s;
    for (string::iterator i = s.begin(); i != s.end(); ++i)
    {
              if (isupper(*i))
                        ++upper;
              else if (islower(*i))
                        ++lower;
    }
    cout << "upper: " << upper << '\n';
    cout << "lower: " << lower << '\n';
    cout << "convert to lowercase? ";
    cin >> c
    if (c == 'y' || c == 'Y')
              // convert string to lowercase
    Detailed understanding of language features - even of all features of a language - cannot compensate for lack of an overall view of the language and the fundamental techniques for using it. - Bjarne Stroustrup

  13. #13
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    Grrrr... almost got it

    almost....

    I got it to accept a command to change the string to the users choice, but when I choose to change to all lowercase I still get all uppercase

    Here it is so far:

    Code:
    #include <cctype> 
    #include <iostream> 
    using namespace std;
    
    using std::cout;
    using std::endl;
    
    int main(void)
    {
    	char sent[] = "";
    	char* x=0;
    	char c=0;
    	int ucase=0;
    	int lcase=0;
    		cout << "Input Your String: " << sent << endl;
    		cin>> sent;
    
    	for(int i=0;i<strlen(sent);i++){
    
    		if((sent[i]>90)&&!(sent[i]==32)){
    			sent[i]=sent[i]-32;
    			lcase++;
    }
    		if(sent[i]==32)ucase--;
    }
    
    	ucase =strlen(sent)-lcase+ucase; 
    
    		cout<<"There were "<<ucase<<" uppercase letters in the string"<<endl;
    		cout<<"There were "<<lcase<<" lowercase letters in the string"<<endl;
    		cout<<"Change the case of the string to upper or lower? (U or L)" <<endl;
    		cin>>c;
    		if (c == 'u' || c == 'l'){
    		}
    		cout<<sent;
    
    
    return 0; 
    }
    HELP!! hehe

  14. #14
    Registered User slaveofthenet's Avatar
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    Your code is riddled with errors. Since you put using namespace std; at the top, you don't need using std::cout or using std::endl. You don't properly allocate space for the string. The main loop is converting all of the character to uppercase, and the if statement at the bottom is doing nothing.
    Code:
    #include <iostream>
    #include <cctype>
    #include <string>
    #include <algorithm>
    
    using namespace std;
    
    int main()
    {
    	string s;
    	int lower = 0, upper = 0;
    	char c;
    	cout << "enter string: ";
    	cin >> s;
    	for (string::iterator i = s.begin(); i != s.end(); ++i)
    	{
    		if (islower(*i)) ++lower;
    		else if (isupper(*i)) ++upper;
    	}
    	cout << "upper: " << upper << '\n';
    	cout << "lower: " << lower << '\n';
    	cout << "convert to upper or lower case (u/l)? ";
    	cin >> c;
    	if (c == 'l' || c == 'L')
    		transform(s.begin(), s.end(), s.begin(), tolower);
    	else if (c == 'u' || c == 'U')
    		transform(s.begin(), s.end(), s.begin(), toupper);
    	cout << s;
    	return 0;
    }
    Detailed understanding of language features - even of all features of a language - cannot compensate for lack of an overall view of the language and the fundamental techniques for using it. - Bjarne Stroustrup

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