Checking if a string contains a substring C++

I’m trying to make a program that checks if a string contains a substring of another string, but it’s not working.

Here is my code:

#include <iostream>
#include <algorithm>

using namespace std;

//Struct to store information
struct strings {
    char string1[20], string2[20];
} strings;

//Function to check if the strings are equal
void equalCheck(){
    int check = 0, i = 0;
    while (strings.string1[i] != '\0' || strings.string2[i] != '\0'){
        if (strings.string1[i] != strings.string2[i]){
            check = 1;
            break;
        }
        i++;
    }
    if (check == 0){
        cout << "The strings are equal" << endl;
    }
    else
        cout << "The strings are not equal" << endl;

}

//Function to check for a substring
void substringCheck(){
    if (strings.string1.find(strings.string2) != string::npos) {
        cout << "found!" << '\n';
    }

}

int main() {


    //Ask the user for two strings
    cout << "Please type the first string: ";
    cin >> strings.string1;
    cout << "Please type the second string: ";
    cin >> strings.string2;

    //Prints out the two strings
    //cout << "The two strings are " << strings.string1 << " and " << strings.string2;

    equalCheck();
    substringCheck();

    return 0;
}

This is the problem I get:

Problem

Any ideas? This is the first time I use C++ and I’m trying to use my basic C knowledge!

Thanks 🙂

>Solution :

Wouldn’t it be easier for strings to have two std::string instead of two char[20]?

Then you would be able to say this with no problem:

if (strings.string1.find(strings.string2) != std::string::npos) {
    std::cout << "found!" << '\n';
}

char is not a class like std::string, it doesn’t have any member functions. This means char[20].find doesn’t exist. std::string is a class, however. And it does have a member function called std::string::find(), so doing this to a std::string is legal.

Leave a Reply