How to convert first letter to uppercase in c++? [closed] - c++

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I have a Structure
struct StudentRecord{
char StudentFamilyName[20]
}gRecs[50];
cout << "Family Name: ";
cin >> gRecs[50].StudentFamilyName;
char str[20];
str[20] = toupper(gRecs[i].StudentFamilyName[0]);
cout << str;
What i want to do is to store the first letter of family name as
upper case and the rest as lower case? How do I do that?
I used toupper but when I implement it doesnot work. Could anyone help me out? Thank you.
Note: This was an exam question.

Answer 1

Here's how to capitalize a string using character arithmetic:
#include <iostream>
#include <string>
using namespace std;
string ToCapitalize(string input)
{
if (input.length() > 1 && input[0] >= 'a' && input[0] <= 'z')
{
input[0] -= 32;
}
return input;
}
int main() {
std::string StudentFamilyName("smith");
cout << StudentFamilyName << std::endl;
cout << "Capitalized: " << ToCapitalize(StudentFamilyName) << endl;
}

Answer 2

Your problem isn't with toupper. There are a couple of them, actually.
cin >> gRecs[50]
gRecs is size 50, so index 50 is out of bounds. To insert into the first record you would use
cin >> gRecs[0].StudentFamilyName;
Second record: gRecs[1], etc.
Next,
char str[20];
str[20] = toupper(str[0]);
You declare str in which nothing is populated, and then call toupper on it.
And the index ([20]) is the 21st character (which is out of bounds). You are attempting to convert the 21st character in the str toupper.
What you need is something like:
// i is the index into your student records array, possibly in a loop
cin >> gRecs[i].StudentFamilyName;
gRecs[i].StudentFamilyName[0] = toupper(gRecs[i].StudentFamilyName[0]);