c - 需要帮助查找 C 程序中的错误(与 char** 复制相关)

Question

我尝试了将 char** 复制到 char** 的不同方法，但一切似乎都不成功。这是我的代码:

void allocate(char ***words, unsigned long stringLength){
    *words = malloc(sizeof(char*) * stringLength);
    for (int i = 0; i < stringLength; i++)
        (*words)[i] = malloc(stringLength);
}

int main(int argc, char **argv){

char **charArray;
allocate(&charArray, strlen(argv[2]));

int i, j;

for(i = 1; i < argc; i++){
    argv++;
    j = 0;
    while((*argv)[j]){
        (*charArray)[j] = (*argv)[j];
        j++;
    }
    charArray++;
}

printf("%s\n", charArray[0]);
printf("%s\n", charArray[1]);
return 0;
}

打印语句不会从参数列表中打印正确的单词，看起来它打印了一些空格..我不知道为什么它不起作用。我不确定这是否是空间分配或指针运算的问题。我希望你能帮我解决这个问题。谢谢

Answer 1

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void allocate(char ***words, int argc, char **argv){
    *words = malloc(sizeof(char*) * argc);
    for (int i = 0; i < argc; i++)
        (*words)[i] = malloc(strlen(argv[i])+1);
}

int main(int argc, char **argv){
    char **charArray;
    allocate(&charArray, argc-1, argv+1);

    int i,j;
    char **pp = charArray;
    for(i = 1;i < argc; i++){
        argv++;
        j = 0;
        while((*argv)[j]){
            (*pp)[j] = (*argv)[j];
            j++;
        }
        (*pp)[j] = '\0';
        pp++;
    }
    printf("%s\n", charArray[0]);
    printf("%s\n", charArray[1]);
    for(int i=0; i < argc-1; ++i)
        free(charArray[i]);
    free(charArray);
    return 0;
}

<小时/>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void makeCopyOfArgv(char ***words, int argc, char **argv){
    *words = malloc(sizeof(char*) * argc);
    for (int i = 0; i < argc; i++){
        (*words)[i] = calloc(strlen(argv[i])+1, sizeof(char));
        for(int j = 0; argv[i][j] ; j++)//use strcpy
            (*words)[i][j] = argv[i][j];
    }
}

int main(int argc, char **argv){
    char **charArray;
    makeCopyOfArgv(&charArray, argc-1, argv+1);

    printf("%s\n", charArray[0]);
    printf("%s\n", charArray[1]);
    for(int i=0; i < argc-1; ++i)
        free(charArray[i]);
    free(charArray);
    return 0;
}