// A simple atoi() function int myAtoi(char *str) { int res = 0; // Initialize result int sign = 1; // Initialize sign as positive int i = 0; // Initialize index of first digit // If number is negative, then update sign if (str[0] == '-') { sign = -1; i++; // Also update index of first digit } // Iterate through all digits and update the result for (; str[i] != '\0'; ++i) res = res*10 + str[i] - '0'; // Return result with sign return sign*res; }