#include<iostream>
#define D 50
using namespace std;
int replace(char *str, char c1, char c2);  //把字符串里char c1的字符改成char c2
int main()
{
    char *arr="a5a5a5a5a5a5a5a5a5a";
    int z;
   
    z = replace(arr, 'a', 'c');
    cout << "字符串:" << arr << endl;
    cout << "有" << z << "个字符a转换成c." << endl;

    system("pause");
    return 0;
}


int replace(char *str, char c1, char c2)
{
    int i = 0;
    char *st;
    st = str;
    while (st!='\0')
    {
        if (*st == c1)
        {
            i++;
            *st = c2;
        }
        st++;
    }
    return i;
   
}
大神来看看怎么回事?

0x00A45D62 处的第一机会异常(在 测试.exe 中):  0xC0000005:  写入位置 0x00A4CC70 时发生访问冲突。
0x00A45D62 处有未经处理的异常(在 测试.exe 中):  0xC0000005:  写入位置 0x00A4CC70 时发生访问冲突。

线程 0x930 已退出，返回值为 -1073741510 (0xc000013a)。
程序“[7832] 测试.exe”已退出，返回值为 -1073741510 (0xc000013a)。
提示这样的错误

#include<iostream>
#define D 50
using namespace std;
int replace(char *str, char c1, char c2);  //把字符串里char c1的字符改成char c2
int main()
{
    char *arr="a5a5a5a5a5a5a5a5a5a";                 //把这里改成char arr[]="a5a5a5a5a5a5a5a5a5a";  编译器正常  *arr就运行不了~~高手解释下?
     int z;
   
    z = replace(arr, 'a', 'c');
    cout << "字符串:" << arr << endl;
    cout << "有" << z << "个字符a转换成c." << endl;

    system("pause");
    return 0;
}


int replace(char *str, char c1, char c2)
{
    int i = 0;
    char *st;
    st = str;
    while (st!='\0')     //改成while(*st)
    {
        if (*st == c1)
        {
            i++;
            *st = c2;
        }
        st++;
    }
    return i;
   
}