所以基本上我希望我的程序显示以下内容:(
内存地址)(十六进制值的 16 个字节)(字符中的那些十六进制值)
现在,我的格式正确,除了以下行总是返回'0'
,因此没有字符被显示根本:
printf("%c", isgraph(*startPtr)? *startPtr:'.');
最后,我认为我正在使用srand
并且rand
正确,但是我的数组没有被随机的东西填满。它总是一样的。
无论如何,这是代码:
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <time.h>
void DumpMem(void *arrayPtr, int numBytes);
void FillMem(void *base, int numBytes);
int main(void)
{
auto int numBytes;
auto double *doublePtr;
auto char *charPtr;
auto int *intPtr;
srand(time(NULL));
// Doubles
printf("How many doubles? ");
scanf("%d", &numBytes);
doublePtr = malloc(numBytes * sizeof(*doublePtr));
if (NULL == doublePtr)
{
printf("Malloc failed!");
}
printf("Here's a dynamic array of doubles... \n");
FillMem(doublePtr, numBytes * sizeof(*doublePtr));
DumpMem(doublePtr, numBytes * sizeof(*doublePtr));
// Chars
printf("\nHow many chars? \n");
scanf("%d", &numBytes);
charPtr = malloc(numBytes * sizeof(*charPtr));
if (NULL == charPtr)
{
printf("Malloc failed!");
}
printf("Here's a dynamic array of chars... \n");
FillMem(charPtr, numBytes * sizeof(*charPtr));
DumpMem(charPtr, numBytes * sizeof(*charPtr));
// Ints
printf("\nHow many ints? \n");
scanf("%d", &numBytes);
intPtr = malloc(numBytes * sizeof(*intPtr));
if (NULL == intPtr)
{
printf("Malloc failed!");
}
printf("Here's a dynamic array of ints... \n");
FillMem(intPtr, numBytes * sizeof(*intPtr));
DumpMem(intPtr, numBytes * sizeof(*intPtr));
// Free memory used
free(doublePtr);
free(charPtr);
free(intPtr);
}
void DumpMem(void *arrayPtr, int numBytes)
{
auto unsigned char *startPtr = arrayPtr;
auto int counter = 0;
auto int asciiBytes = numBytes;
while (numBytes > 0)
{
printf("%p ", startPtr);
for (counter = 0; counter < 8; counter++)
{
if (numBytes > 0)
{
printf("%02x ", *startPtr);
startPtr++;
numBytes--;
}
else
{
printf(" ");
}
}
printf(" ");
for (counter = 0; counter < 8; counter++)
{
if (numBytes > 0)
{
printf("%02x ", *startPtr);
startPtr++;
numBytes--;
}
else
{
printf(" ");
}
}
printf(" |");
// 'Rewind' where it's pointing to
startPtr -= 16;
for (counter = 0; counter < 16; counter++)
{
if (asciiBytes > 0)
{
printf("%c", isgraph(*startPtr)? *startPtr:'.');
asciiBytes--;
}
else
{
printf(" ");
}
}
puts("| ");
}
}
void FillMem(void *base, int numBytes)
{
auto unsigned char *startingPtr = base;
while (numBytes > 0)
{
*startingPtr = (unsigned char)rand;
numBytes--;
startingPtr++;
}
}
为什么我没有在数组中获得随机值?为什么我的条件语句总是'false'
?