C++编程问题请大神赐教谢谢

Question

下面代码为什么会提示冲突

int replace(char*str, char c1, char c2) {
int count = 0;
int i = 0;
while (*str != '\0') {
if (str[i] = c1){
str[i] = c2;
count++;
}
i++;
}
return count;
}

int main()
{
char A[5] = "abcd";
cout << "count:" << replace(A, 'a', 'f') << endl << "A" << A;
return 0;
}

Answer 1

1、星str表示char数组的第一个元素，所以永远不可能=\0，while死循环，i一直自增，str[i]越界
2、str[i] = c1;是赋值，str[i] = =c1才是判断