1.2 Implement a function void reverse(char* str) in C or C++ which reverses a null- terminated string.

1.2.cpp

#include<iostream>

void reverse(char *str) {
    if (str == nullptr) return;
    
    // find the end of the string
    char *end = str;
    char temp;
    while (*end != '\0') ++end;
    --end;
    
    // swap the begin and end
    while (str < end) {
        temp = *str;
        *str++ = *end;
        *end-- = temp;
    }
}

int main(int argc, char *argv[])
{
    char str[]{"abcde"};
    reverse(str);
    std::cout << str << std::endl;
    return 0;
}