一道有点难度的C语言题目 帮帮小弟

我们有2个array里面有10个elements， 一行是学生的ID， 一行是分数。 学生ID是一个有8个characteristics的string, ((7 numbers plus the end of string mark '\0',  A valid student numbers start with a '1', an input of 0 is used to exit the program, 这个是说每个学生ID后面加'\0'， 输入开头字母是1的学生ID 能查成绩， 如果输入第一个数字是0就推出程序）。
写一个C编程 里面有2个input， ID 和 mark
如果 学生ID 存在， 那么出现成绩
如果不存在 就出现 no marks

英文原文见下

We have  two arrays of  10 elements: a list of students IDs and a list of marks.  The main method and  test data is defined in the file attached.  
The student ID is a string with 8 characters (7 numbers plus the end of string mark '\0',  A valid student numbers start with a '1', an input of 0 is used to exit the program. 
 
Write the  function called update_mark  which has  two input parameters:  a student ID and a mark.

    If the student exist, it will increment  their mark and print the new mark.
     If it does not exist it will print a message saying so. 

 
Hint: review the code you wrote in the workshop for find. Now you need to find a string instead of an integer, and use the index of the student ID to update their mark

答案：#include <stdio.h>

void main()
{
 int price[4] = ;
 int num[4] = ;
 int sum = 0;
 for (int i = 0; i < 4; i++)
 {
  sum += price[i]*num[i];
 }
 printf("The total money is %d.\n", sum);
}

……难点何在？还是我理解错意思了？

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