一：功能
iota 是给定一个初始元素，然后依次对序列中每个元素进行递增 操作，详见代码一；
atoi 是将字符串转换成整数；atol, atoll 将字符串转换成长整型数 long，long long。
二：用法
#include#include #include int main() { std::vector data(9, 0); for (auto v : data) std::cout << v << " "; std::cout << "\n"; //对序列中元素进行累加， -4是初始值 std::iota(data.begin(), data.end(), -4); for (auto v : data) std::cout << v << " "; std::cout << "\n"; //4 -3 -2 -1 0 1 2 3 4 }
#include#include int main(void) { printf("%i\n", atoi(" -123junk")); printf("%i\n", atoi(" 321dust")); printf("%i\n", atoi("0")); printf("%i\n", atoi("0042")); // treated as a decimal number with leading zeros printf("%i\n", atoi("0x2a")); // only leading zero is converted discarding "x2a" printf("%i\n", atoi("junk")); // no conversion can be performed printf("%i\n", atoi("2147483648")); // ub: out of range of int }
