我在编译程序时遇到问题，我不确定我的逻辑和/或语法是否正确。我正在尝试做的是制作一个大小（由用户定义）字符串的数组，每个字符串有 20 个字符。
//Melissa P.
//University of Massachusetts Dartmouth
//CIS362
//2-6-2016
#include <stdio.h>
#define MIN 0 //For the random number generator
#define MAX 51 //so it can properly choose randomly a letter from my given array in getRandomString function
int getNum(void);
char * getRandomString(void);
int main (void)
{
int input = 0;
int i = 0;
int j = 0;
char word[20]; //placeholder for the random string result
printf("How many strings do you want in the array? "); //questions the user for amount of 20 character strings
scanf("%d", &input);
const char *array[input]; //pointer array of size defined by user
for (i = 0; i < input; i++)
{
*word = getRandomString(); //gets the 20 character string from the function
array[i] = *word; //and puts it in each space of the array
}
for (i = 0; i < input; i++)
{
printf("%sn", array[i]); //prints the array
}
}
int getNum() //function to get a random number between 0 and 51.
{
int num;
num = rand()% ((MAX + 1) - MIN) + MIN;
return num;
}
char * getRandomString(void)
{
char word[20]; //declares the array for the random word to go in.
int num = 0;
int i = 0;
char letterArray[52] = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l',
'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x',
'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V',
'W', 'X', 'Y', 'Z'}; //array of all lower case and upper case letters
for (i = 0; i < 20; i++)
{
num = getNum(); //gets a random number seed
word[i] = letterArray[num]; //fills the word array with a random letter
}
word[i] = ' ';
return *word; //returns the string
}
我得到的错误是这样的："赋值在没有强制转换的情况下从指针生成整数"这发生在 main 和 getRandomString 方法中。谢谢！
你的代码有很多错误，我已经纠正了你的错误，试试：
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define MIN 0 //For the random number generator
#define MAX 51 //so it can properly choose randomly a letter from my given array in getRandomString function
int getNum(void);
char * getRandomString(void);
int main (void)
{
int input = 0;
int i = 0;
int j = 0;
char* word; //placeholder for the random string result
printf("How many strings do you want in the array? "); //questions the user for amount of 20 character strings
scanf("%d", &input);
char **array = malloc(input * sizeof(char*)); //pointer array of size defined by user
for (i = 0; i < input; i++)
{
array[i] = malloc(21);
}
for (i = 0; i < input; i++)
{
word = getRandomString(); //gets the 20 character string from the function
strcpy(array[i],word); //and puts it in each space of the array
free(word);
}
for (i = 0; i < input; i++)
{
printf("%sn", array[i]); //prints the array
}
//free memory
for (i = 0; i < input; i++)
{
free(array[i]);
}
free(array);
}
int getNum() //function to get a random number between 0 and 51.
{
int num;
num = rand()% ((MAX + 1) - MIN) + MIN;
return num;
}
char * getRandomString(void)
{
char* word = malloc(21); //declares the array for the random word to go in.
int num = 0;
int i = 0;
char letterArray[52] = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l',
'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x',
'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V',
'W', 'X', 'Y', 'Z'}; //array of all lower case and upper case letters
for (i = 0; i < 20; i++)
{
num = getNum(); //gets a random number seed
word[i] = letterArray[num]; //fills the word array with a random letter
}
word[i] = ' ';
return word; //returns the string
}
研究更好的指针，你必须使用string.h来表示strcpy函数，使用stdlib.h来表示malloc。
我看到的问题：
改进getRandomString的建议
getRandomString有几个问题。
char* getRandomString(void)
{
char word[20];
int num = 0;
int i = 0;
char letterArray[52] = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l',
'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x',
'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V',
'W', 'X', 'Y', 'Z'};
/// Problem ///
/// When you have an array of 20 characters for a string
/// you can fill at most 19 characters. The 20-th character
/// needs to be the null character.
for (i = 0; i < 20; i++)
{
num = getNum();
word[i] = letterArray[num];
}
/// Problem ///
/// By the time you are here, i is 20, one more than the highest valid index.
/// You need to terminate the for loop with the conditional
/// i < 19
word[i] = ' ';
/// Problem ///
/// *word evaluates to the first character of the string.
/// The type it evaluates to is char, which does not match the
/// return type of the function. Changing to "return word;" will
/// be syntactically correct but that will be a problem. You will
/// be returning a pointer to a string which lives only as long
/// the function lives. The pointer will be a dangling pointer in
/// the calling function.
return *word;
}
您可以将其更改为：
char* getRandomString(void)
{
char word[20];
int num = 0;
int i = 0;
char letterArray[52] = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l',
'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x',
'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V',
'W', 'X', 'Y', 'Z'};
// Stop the loop when i is 19
for (i = 0; i < 19; i++)
{
num = getNum();
word[i] = letterArray[num];
}
word[i] = ' ';
// Return a string that is a copy of word.
// The pointer will be valid in the calling function.
return strdup(word);
}
上述版本的 getRandomString 返回指向动态分配的内存的指针。在调用函数中，您必须释放内存。
改进main的建议
从以下位置删除const：
const char *array[input];
来得及
char *array[input];
从main中删除word的定义。你不需要它。捕获从getRandomString返回的值所需的只是：
for (i = 0; i < input; i++)
{
array[i] = getRandomString();
}
函数结束之前添加以下代码块以释放内存。
for (i = 0; i < input; i++)
{
free(array[i]);
}
添加必要的#include语句
你需要string.h才能strdup，stdlib.h才能rand。加
#include <string.h>
#include <stdlib.h>
在文件的顶部。