Check out example codes for "string to int c". It will help you in understanding the concepts better.

Code Example 1

atoi(str) is unsafe

This is the prefered method:
(int)strtol(str, (char **)NULL, 10)

Code Example 2

#include<string>
string str1 = "45"; 
string str2 = "3.14159"; 
string str3 = "31337 geek";

int myint1 = stoi(str1);
std::cout<<stoi(str1);

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