Convert String to Integer (str to int) using C++ [Urdu / Hindi]

Convert string to integer in C++

In this video, we are going to solve a C++ programming problem where are given a string and we have to convert it into an integer (str to int). In this video, we will try to handle all the cases that might break our code.

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Source Code:

#include <iostream>
#include <cstring>
#include <string_view>

int64_t str_to_int64(std::string_view number) {
    int64_t converted_number{};
    bool is_positive{ true };
    size_t valid_pos{};

    // Skipping to the actual number (if found)
    for (auto each : number)
    {
        if (isdigit(each)) break;
        valid_pos++; // 1
    }

    // Checking for negative number
    if (valid_pos > 0 and number[valid_pos-1] == '-') is_positive = false;

    // Actual conversion
    for (size_t i{valid_pos}; i < number.length() and isdigit(number[i]); i++) // 3, 3
    {
        converted_number *= 10;                 // 238
        converted_number += number[i] - 48;     // 8
    }

    return is_positive ? converted_number : -converted_number;
}

int main() {
    std::string str_number{ "      32fw5eoi" };

    auto number {str_to_int64(str_number)};

    std::cout << number << '\n';

}

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