c - C 将字符输入数组时出现段错误

Question

我试图将各种核苷酸碱基输入到阵列中，但我的阵列出现问题。它要么在我输入一个字符后返回段错误，要么在提示我输入另一个字符之前循环运行 3 次。感谢您提前提供的帮助。

这是我的代码:

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

int main(void)
{
    char strand[20];
    char nucleotide;
    int position=0;

    while(position<20)
    {
        printf("Enter one capital character:\n");
        scanf("%c",nucleotide);
        if(toupper(nucleotide) == 'A')
        {
            printf("You entered an A\n",nucleotide);
            strand[position] = nucleotide; // store the letter in an array
            position = position + 1; // gives the new letter a position in the array
        }
        else if(toupper(nucleotide) == 'G')
        {
            printf("You entered a G\n");
            strand[position] = nucleotide; // store the letter in an array
            position = position + 1; // gives the new letter a position in the array
        }
        else if(toupper(nucleotide) == 'C')
        {
            printf("You entered a C\n");
            strand[position] = nucleotide; // store the letter in an array
            position = position + 1; // gives the new letter a position in the array
        }
        else if(toupper(nucleotide) == 'U')
        {
            printf("You entered a U\n");
            strand[position] = nucleotide; // store the letter in an array
            position = position + 1; // gives the new letter a position in the array
        }
        else
        {
            printf("You have not entered a valid character.\n Please enter a character found in an RNA strand.\n");
        }
        printf("Congratulations, you entered %c\n",nucleotide);
    }
    return 0;
}

Answer 1

你的错误是scanf("%c",核苷酸);用scanf("%c",&核苷酸);更改它，因为scanf接受指针作为参数.

此外，您不需要知道输入了哪个字符，您可以这样做:

#include<stdio.h>
#include<ctype.h>

int main(void) {
    char strand[20];
    char nucleotide;
    int  position = 0, i;

    while (position < 20) {
        printf("Enter one capital character:\n");
        scanf("%c", &nucleotide);

        if (toupper(nucleotide) == 'A' || toupper(nucleotide) == 'G' || toupper(nucleotide) == 'C' ||
            toupper(nucleotide) == 'U') {
            printf("You entered an %c\n", toupper(nucleotide));
            strand[position] = nucleotide; // store the letter in an array
            ++position;// gives the new letter a position in the array
        } else
            printf("You have not entered a valid character.\n Please enter a character found in an RNA strand.\n");

        printf("Congratulations, you entered %c\n", nucleotide);
    }

    printf("Your sequence is: ");
    for (i = 0; i < 20; ++i)
        printf("%c", strand[i]);
    printf("\n");
    return 0;
}