尝试返回字符指针时出现奇怪的输出

Question

编辑：我删除了内存分配声明并将strlen（bufferPointer）更改为strlen（inputLine）。这似乎摆脱了我的输出中的怪异符号。

我想写一个方法来删除字符串中的第一个单词，并返回删除单词的字符指针。由于这个词被删除，字符串的大小应该减少。

我遇到了一个奇怪的输出，我不知道为什么。

我对C相当陌生，刚开始熟悉指针的想法，所以任何帮助将不胜感激！

//global variables 
char inputLine[] = "Hello there, my name is bob"; 
char *bufferPointer = inputLine; 
char *nextWord(); 

main(){ 
    printf("%s\n", nextWord()); 
} 

char *nextWord(){ 
    //calling a method that returns the number of words bufferPointer holds 
    int numOfWords = nwords(bufferPointer); 
    char *tmp2; 

    //Allocate memory to newArray 
    char *newArray = malloc(sizeof(char)*strlen(bufferPointer)); 

    //create backup array 
    char backup[strlen(bufferPointer)]; 
    strncpy(backup, bufferPointer, strlen(bufferPointer)); 
    backup[strlen(bufferPointer)] = '\0'; 

    //assign newArray pointer to backup array 
    newArray = backup; 

    //allocate memory to token (returned variable) 
    char *token = malloc(sizeof(char)*strlen(bufferPointer)); 
    token = strtok(newArray, " "); 

    char *tmp = strchr(bufferPointer, ' '); 
    //move pointer to next word 
    if (tmp != NULL){ 
     tmp2 = tmp; 
     bufferPointer = tmp +1; 
    } 
    return token; 
} 

旧输出是：

there, 
my 
?²p 
?? 
?²p? 
?²p? 

新的输出是：

there, 
my 
name 
is 
bob 

Answer 1

strlen()只给你的字符数，除空字符。您还需要为空字符分配内存。

Answer 2

您正在返回令牌。相反，你应该返回bufferPointer。

return bufferPointer. 

而只是指出，代码中有几处内存泄漏。

根据您的要求，以下是要点。

上述程序中的内存泄漏如下所示。

//Allocate memory to newArray 
char *newArray = malloc(sizeof(char)*strlen(bufferPointer)); 
// A memory address is given to newArray here which is 
// over-written in following statement. So the above allocated 
// memeory is a leak. 
newArray = backup; 

//allocate memory to token (returned variable) 
char *token = malloc(sizeof(char)*strlen(bufferPointer)); 
token = strtok(newArray, " "); 
//There is no need to allocate memory to hold an address of a string. 
// only a character pointer is enough. So, the above allocated memory 
// is again a leak. 

而且还有两个额外的变量定义，这是不必要的。

1）的可变bufferPointer可以与inputLine因为字符数组的名称替换也是C.

2）的指针不使用numOfWords任何地方都没有。