C语言百分比计算程序运行异常，请求问题排查与解决

你的程序运行异常主要源于三个核心错误：

1. 数组越界访问 #

printf("\nPlease enter the value of %s:\n", name1[25]); 中，name1[25]是访问数组的第26个元素（C语言数组下标从0开始，name1[25]的有效下标范围是0-24），属于数组越界操作，会触发未定义行为，直接导致程序崩溃或异常退出。正确写法是直接传入数组名name1。

2. 输入缓冲区残留问题 #

scanf("%i", &value1); 读取整数后，会将用户输入的换行符留在输入缓冲区中，后续的fgets会直接读取这个换行符，误认为用户输入了空内容，导致程序跳过后续输入步骤直接结束。需要在每次scanf后清空输入缓冲区。

3. 变量赋值错误 #

所有scanf都指向&value1，会导致后续输入的数值全部覆盖value1的值，value2到value5始终未被赋值，完全不符合程序设计逻辑，需对应修改为&value2、&value3等。

另外，fgets会将用户输入的换行符一并读取到数组中，打印时会多出换行，建议用strcspn去除换行符。

修正后的完整代码 #

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

int main (){
    
    char name1[25] ;
    char name2[25] ;
    char name3[25];
    char name4[25];
    char name5[25];

    int value1 ;
    int value2 ;
    int value3 ;
    int value4 ;
    int value5 ;
    
    printf ("Hello mortal, this program allows you to calculate percentages of five parts that are the only components of the whole.\n");
    
    // 第一个变量输入
    printf ("\nPlease enter your 1st variable that you want to calculate the percentage of without any spaces:\n");
    fgets (name1, 25, stdin);
    // 去除fgets读取的换行符
    name1[strcspn(name1, "\n")] = '\0';
    printf ("\nPlease enter the value of %s:\n", name1);
    scanf ("%i", &value1);
    // 清空scanf残留的换行符
    while(getchar() != '\n');
    
    // 第二个变量输入
    printf ("\nPlease enter your 2nd variable that you want to calculate the percentage of without any spaces:\n");
    fgets (name2, 25, stdin);
    name2[strcspn(name2, "\n")] = '\0';
    printf ("\nPlease enter the value of %s:\n", name2);
    scanf ("%i", &value2);
    while(getchar() != '\n');
    
    // 第三个变量输入
    printf ("\nPlease enter your 3rd variable that you want to calculate the percentage of without any spaces:\n");
    fgets (name3, 25, stdin);
    name3[strcspn(name3, "\n")] = '\0';
    printf ("\nPlease enter the value of %s:\n", name3);
    scanf ("%i", &value3);
    while(getchar() != '\n');
    
    // 第四个变量输入
    printf ("\nPlease enter your 4th variable that you want to calculate the percentage of without any spaces:\n");
    fgets (name4, 25, stdin);
    name4[strcspn(name4, "\n")] = '\0';
    printf ("\nPlease enter the value of %s:\n", name4);
    scanf ("%i", &value4);
    while(getchar() != '\n');
    
    // 第五个变量输入
    printf ("\nPlease enter your 5th variable that you want to calculate the percentage of without any spaces:\n");
    fgets (name5, 25, stdin);
    name5[strcspn(name5, "\n")] = '\0';
    printf ("\nPlease enter the value of %s:\n", name5);
    scanf ("%i", &value5);
    while(getchar() != '\n');

    // 百分比计算逻辑
    int total = value1 + value2 + value3 + value4 + value5;
    printf("\n--- 百分比结果 ---\n");
    printf("%s: %.2f%%\n", name1, (float)value1 / total * 100);
    printf("%s: %.2f%%\n", name2, (float)value2 / total * 100);
    printf("%s: %.2f%%\n", name3, (float)value3 / total * 100);
    printf("%s: %.2f%%\n", name4, (float)value4 / total * 100);
    printf("%s: %.2f%%\n", name5, (float)value5 / total * 100);

    return 0;
}

内容的提问来源于stack exchange，提问作者Bruno Duarte