How do I change the first letter to uppercase?

[musicman74]

I need help with changing information in a file.

This program access the file and changes the all uppercase sentenced to lower case. I used the tolower function.
The trick how do I make the first letter of each sentence uppercase. I know I can use toupper but how do I tell the program where to use it. The sentences will change so they are not fixed in length.

// This program takes uppercase sentences from one file and makes them lowercase
#include <iostream>
#include <fstream>
#include <string>
#include <cctype>  
using namespace std;

int main()
{
    string fileName;         // Holds filename
    char ch;                 // Holds a character
    ifstream inFile;         // Input file
    
    // Open file for output.
    ofstream outFile("challengeOut.txt");
    
    // Get the input file.
    cout << "Enter a file name: ";
    cin >> fileName;
    
    // Open file for input.
    inFile.open(fileName.c_str());
    
    // If input file opened successfully, continue.
    if (inFile)
    {
       // Read char from file 1.
       inFile.get(ch);
       
       // If last read operation was successful.
       while (inFile)
       {
             //Write lowercase char to file 2.
             outFile.put(tolower(ch));
             
             // Read another char from file 1.
             inFile.get(ch);
       }
       
       // Close files.
       inFile.close();
       outFile.close();
       cout << "File conversion done.\n";
    }
    else
        cout << "Cannot open " << fileName << endl;
    system("pause");
    return 0;
}

[giblit]

After every newline character just use toupper instead. You could also read it into a string and just do str[0] = toupper(str[0]);

[musicman74]

That's the problem I can't figure out how to tell the computer what to do AFTER the new line. I know I can tell it if (ch = '\n') but I don't know how to tell it to manipulate the next character. I also don't know how to get the very first letter capitalized. I have not worked with strings yet, but it looks like an array. Is it assigned the same way?

[eyenrique]

Hi @musicman74,
i can figure out now
a way using toupper
and strings (std::string)

but to be honest idk
if its the best;

this is a little example;

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39

//FirstLetter.cpp //## #include <iostream> #include <string> #include <cstring> using namespace std; int main(){ int const NUMBER_OF_NAMES=3; string names[NUMBER_OF_NAMES]; names[0]="emily"; names[1]="ariel"; names[2]="beck"; //output 3 names for(int i=0;i<NUMBER_OF_NAMES;i++) cout<<names[i]<<endl; //changing first letter for(int i=0;i<NUMBER_OF_NAMES;i++) names[i].at(0)=toupper(names[i].at(0)); //printing again cout<<'\n'; for(int i=0;i<NUMBER_OF_NAMES;i++) cout<<names[i]<<endl; return 0; //indicates success }//end of main

Eyenrique$ ./FirstLetter emily ariel beck Emily Ariel Beck

[musicman74]

I don't know if that will work or not the sentences are in a file and they have to be changed from uppercase to lowercase with the first letter capitalized. So it's reading one letter at a time. I really just need to know how to signify I only want the first letter of each sentence then I can use toupper.

[giblit]

std::ifstream in("input.txt");
std::ofstream out("output.txt");
std::string line;
while(std::getline(in, line)
{
    line[0] = toupper(line[0]);
    for(std::size_t i = 1; i < line.size(); ++i) line[i] = tolower(line[i]);
    out << line << std::endl;
}

You can iterate different ways or even use std::transform. There are numerous ways to make all but first lower case.

Here is my favorite. std::transform(line.begin() + 1, line.end(), line.begin() + 1, tolower);

http://coliru.stacked-crooked.com/a/40f46e29779eb47e

[musicman74]

Thank you. I think I get it. I'll give it a shot and let you know how it works.