C语言实现学生成绩计算器时无法通过输入字符串正常终止循环

API 探路者

2026-9-26

具体修改方案

你只需要调整3处代码即可实现需求：

将原循环内的输入提示文字修改，告知用户输入UNKNOWN即可终止程序
替换退出判断逻辑：C语言中字符串匹配不能直接用==对比，需要调用<string.h>头文件中提供的strcmp()函数，两个字符串完全一致时函数返回值为0，以此作为退出条件
修正原代码中scanf("%s", &name)的写法错误：数组名本身就是内存首地址，不需要额外加取地址符&

修改后的完整代码

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

int main() {
  float grade1, grade2, grade3, grade4;
  char name[32];

  printf("Welcome to the Student Quiz Calculator Program\n");

  while (1) {
    // 修改提示文字
    printf("Enter a student name. Enter 'UNKNOWN' to quit: \n");
    // 去掉多余的&符号
    scanf("%s", name);

    // 替换为字符串匹配判断逻辑
    if (strcmp(name, "UNKNOWN") == 0) {
      printf("Thanks for using the calculator. Bye!\n");
      break;

    } else {
      printf("Enter quiz grade 1: ");
      scanf("%f", &grade1);
      printf("Enter quiz grade 2: ");
      scanf("%f", &grade2);
      printf("Enter quiz grade 3: ");
      scanf("%f", &grade3);
      printf("Enter quiz grade 4: ");
      scanf("%f", &grade4);

      float average = (grade1 + grade2 + grade3 + grade4) / 4;
      printf("%s, with grades of %.0f, %.0f, %.0f, and %.0f, your quiz average is %0.2f!\n", name, grade1, grade2, grade3, grade4, average);
    }
  }
  // 补充main函数返回值，符合C语言规范
  return 0;
}