编写自定义函数int ctoi(char s[])，将字符串转换为对应的整数。其中

s是一个只包含数字的字符数组，函数返值为转换后所得整数。在main函数中验证结果。例如，字符串“512”转换后得到整数512。-Write a custom function int ctoi (char s []), to convert the string to the corresponding integer. Where s is a character array containing only numbers, the function returns the resulting integer value after the conversion. Verify the results in the main function. For example, after the character string " 512"　converted integer 512.