如何在不使用sprintf的情况下在C中连接字符串和int？

int num = 123;
char str[20];
itoa(num, str, 10); // 将整数转换为字符串
strcat(str, " is a number."); // 连接字符串

int num = 123;
char str[20];
snprintf(str, sizeof(str), "%d is a number.", num); // 格式化整数为字符串

int num = 123;
char str[20];
int temp = num;
int count = 0;
while (temp != 0) {
    temp /= 10;
    count++;
}
temp = num;
for (int i = count - 1; i >= 0; i--) {
    str[i] = '0' + (temp % 10); // 将每一位转换为字符
    temp /= 10;
}
str[count] = '\0';
strcat(str, " is a number."); // 连接字符串