在C中复制python字符串行为

Question

I'm trying to learn C, and I thought a good way to do so was to rework some programing praxis problems that I did in python. I'm currently working on this one.

My solution:

def main():
    nums = ["10", "9", "8", "7", "6", "5", "4", "3", "2", "1"]
    ops = ["+", "-", "*", "/", ""]

    recursive(nums, ops, "", 0)

def recursive(nums, ops, current_str, num_ind):
    if num_ind == len(nums)-1:
        # print current_str + nums[num_ind]
        if eval(current_str + nums[num_ind]) == 2013:
            print current_str + nums[num_ind]
        return 0
    else: 
        current_str = current_str + nums[num_ind]
        num_ind += 1
        for i in range(len(ops)):
            recursive(nums, ops, current_str+ops[i], num_ind)

Python performs some witchery when doing recursive function calls where it creates a new string per function call ie "" results in "10" which results in "10+", "10-", "10*", "10/", "10" so on and so forth for every permutation. An example if you uncommented that print statement:

10+9+8+7+6+5+4+3+2+1
10+9+8+7+6+5+4+3+2-1
10+9+8+7+6+5+4+3+2*1
10+9+8+7+6+5+4+3+2/1
10+9+8+7+6+5+4+3+21

Seeing how hands on you have to be with memory allocation and strings in C, is it even possible to do that sort of "forking" behavior that python exhibits in C?

UPDATE:

Figured it out,

int recursive(char** nums, char** ops, char* current_str, int num_ind){
    int i, ret;
    char new_str[100];

    num_ind++;
    if(num_ind == 9){
        //printf("%s\n", strcat(current_str,nums[num_ind]));
        ret = eval(strcat(current_str, nums[num_ind]));
        if(ret == 2013){
            printf("%s\n", current_str);
        }
        return 0;
    }
    for(i=0; i<5; i++){
        strcpy(new_str, current_str);
        strcat(new_str, nums[num_ind]);
        recursive(nums, ops, strcat(new_str, ops[i]), num_ind);
    }
}

Answer 1

Of course you can. Use malloc and free to allocate memory for each invocation. Some very complex program that process text, like a compiler, are written in C. They are just hugely painful compare to Python. Or you can use C++, which has a string class so that you can do basic thing like string concatenation more easily.