Question

How to convert a string to an integer in C++

Answer 1

#include <iostream>
#include <string>
 
int main() {
    std::string str = "84372";
     
    int num = std::stoi(str);
 
    std::cout << num;
}

 
 
/*
run:
 
84372
 
*/

 

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Answer 2

#include <iostream>
#include <string>
#include <sstream>

int main() {
    std::string str = "84372";
    
    int num;
    std::stringstream ss(str);
    ss >> num;
    
    std::cout << num;
}

 
 
/*
run:
 
84372
 
*/

 

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Answer 3

#include <iostream>
#include <cstdlib>

int main() {
    const char* str = "84372";
    
    int num = std::atoi(str);
    
    std::cout << num;
}


 
 
/*
run:
 
84372
 
*/

 

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