在 C++ 中的字符串数组中搜索特定字符

Question

The user has to enter 3 strings and we have to put them in an array. Then user enters a char that he wants to find in input strings. Then if the char is found, update the counter for how many times char appeared.

Example:

User input string: Cat Car Watch

User char input: a

Result:

Letter a appears 3 times!

How can I search through a string array like this to find specific chars?

Code below but I'm stuck:

string userString[3];
for (int i = 0; i < 3; i++)
{
    cout << "Input string: ";
    getline(cin, userString[i]);    
}

char userChar;    
cout << "Input char you want to find in strings: ";
cin >> userChar;

int counter = 0;
    
for (int i = 0; i < 3; i++)
{
    if (userString[i] == userChar)
    {
        counter++;
    }
}

cout << "The char you have entered has appeared " << counter << " times in string array!";

Answer 1

Instead of writing for loops manually it is better to use standard algorithms as for example std::count .

Here is a demonstration program

#include <iostream>
#include <string>
#include <iterator>
#include <algorithm>

int main()
{
    std::string words[] = { "Cat", "Car", "Watch" };
    char c = 'a';

    size_t count = 0;

    for ( const auto &s : words )
    {
        count += std::count( std::begin( s ), std::end( s ), c );
    }

    std::cout << "count = " << count << '\n';
}

The program output is

count = 3

If your compiler supports C++ 20 then you can write the program the following way

#include <iostream>
#include <string>
#include <iterator>
#include <ranges>
#include <algorithm>

int main()
{
    std::string words[] = { "Cat", "Car", "Watch" };
    char c = 'a';

    size_t count = std::ranges::count( words | std::ranges::views::join, c );

    std::cout << "count = " << count << '\n';
}

Again the program output is

count = 3

As for your code then this code snippet

for (int i = 0; i < 3; i++)
{
    if (userString[i] == userChar)
    {
        counter++;
    }
}

is incorrect. You need one more inner for loop to traverse each string as for example

for (int i = 0; i < 3; i++)
{
    for ( char c : userString[i] )
    {
        if ( c == userChar)
        {
            counter++;
        }
    }
}