c - 分段故障核心转储......？

Question

我正在努力做到这一点:

Write a program that accepts three user inputs: assignment mark, midterm mark, and final exam mark.

These inputs are of type float and should have values between 0 and 100.

The program should compute the final grade as a percentage and a letter grade.

• Final grades are computed as: Assignments 20%, Midterm 30%, Final exam 50%. Letter grades are computed as: A (final grade ≥ 80%), B (80 > final grade ≥ 70%), C (70 > final grade ≥ 60%), D (60 > final grade ≥ 50%), and F (50 > final grade).

The final grade and letter grade are displayed.

使用以下代码:

#include <stdio.h>

int checkMark(int);
float getMark();
float computeFinalGrade(float assign, float midterm, float finalExam, float finalGrade);
int computeLetterGrade(float);

int checkMark(int x)
{
    while(x<0 || x>100) //While x is a negative number:
    {
        printf("Invalid entry.Try again:");
        scanf("%d",&x);
    }

    if(x>0 && x<=100)//If x is a positive number:
        x=x;

    return x;
}

float getMark(void)
{
    float mark=0,assignMark=0,midMark=0,examMark=0,finalMark=0;
    char letterGrade;


    printf("Enter assignment grade:");
    scanf("%d",mark);

    checkMark(mark);
    assignMark=mark;

    printf("\nEnter midterm mark:");
    scanf("%f",&mark);

    checkMark(mark);
    midMark=mark;

    printf("\nEnter exam mark:");
    scanf("%f",&mark);

    checkMark(mark);
    examMark=mark;


    finalMark=computeFinalGrade(assignMark,midMark,examMark,finalMark);
    letterGrade=computeLetterGrade(finalMark);

    printf("The final grade for the course is %.1f, and the letter grade is %c.\n",finalMark,letterGrade);

    return 0;
}

float computeFinalGrade(float assign, float midterm, float finalExam, float finalGrade)
{
    assign=(float)0.2*assign;
    midterm=(float)0.3*midterm;
    finalExam=(float)0.4*finalExam;

    finalGrade=(float)assign+midterm+finalExam;
    return finalGrade;
}

int computeLetterGrade(float finalGrade)
{
    int grade;

        if(finalGrade>=80)
            grade=65;

        if(finalGrade<80)
            if(finalGrade>=70)
                grade=66;

        if(finalGrade<70)
            if(finalGrade>=60)
                grade=67;

        if(finalGrade<60)
            if(finalGrade>=50)
                grade=68;

        if(finalGrade<50)
            grade=70;

    return grade;
}

int main()
{
    getMark();

    return 0;
}

当我调试上面的程序并输入一个负数时，它会给我这个:

Enter assignment grade:123
Segmentation fault (core dumped)

我究竟做错了什么？

Answer 1

这是你的问题:

scanf("%d",mark);

您需要传递变量的地址，说明符应该是%f。尝试:

scanf("%f", &mark);

顺便说一句，有一个C FAQ关于这个。