string to int c code example

Example 1: string to int c

atoi(str) is unsafe

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

Example 2: c string is int

int isNumber(char s[])
{
    for (int i = 0; s[i]!= '\0'; i++)
    {
        if (isdigit(s[i]) == 0)
              return 0;
    }
    return 1;
}

Example 3: how to string to integer in c++

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

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

Example 4: how to cast string to int in c

use atoi from the stdlib.h 
char *string = "hi";
int x = atoi(string);