Psychobagger Psychobagger - 1 year ago 77
C Question

C (Basic stuff) - Write User Input to a File [self-solved]

Basically, I want to have the user input four names and four grades into a text file (2 columns); just for example:

Mary 98

Mike 60

John 78

Beth 89

I want to be able to read the file (presumably with fscanf) and display the highest/lowest grades, and the average of them. So I would need to create variables for all the inputs, right? In class today, we learned about structures, so I'm assuming one might need to be implemented. I have no actually useful code, but here's the start of it:


int main()

int i;

FILE *Fpointer;
char input[100];
int input2[4];

Fpointer = fopen("file.txt", "w");

for(i = 0; i < 4; i++)
printf("Enter a name>");
scanf("%s", input);
printf("Enter a grade>");
// User Josh Bressers told me to change the below %d to %s
scanf("%s", input2);
// And the second %d to %s here
// The program prints 4 names and 4 numbers perfectly now
fprintf(Fpointer, "%s %s", input, input2);
fprintf(Fpointer, "\n");



return 0;


Now that the program takes the user's input of four names and numbers, how would I read the numbers and do the calculations listed in the first paragraph? Any help is appreciated!




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

// Name of file to be created and data saved in
#define FILENAME "students_and_grades.txt"
// Size of arrays for names
#define NAME_ARRAY_SIZE 25

// Declare arrays
char arrcName1[NAME_ARRAY_SIZE];
char arrcName2[NAME_ARRAY_SIZE];
char arrcName3[NAME_ARRAY_SIZE];
char arrcName4[NAME_ARRAY_SIZE];
char arrcHighestName[NAME_ARRAY_SIZE];
char arrcLowestName[NAME_ARRAY_SIZE];

int main()
printf("----Tyler Procko----\n\n\n");

int iScore1, iScore2, iScore3, iScore4;
int iHighestScore, iLowestScore;
double dScoreAverage;

// Declare file pointer
FILE *Fpointer;

// Open file for writing
Fpointer = fopen(FILENAME, "w");

// Ask user for first student name and score
printf("What is the first student's name? ");
scanf("%s", arrcName1);

// Check range (0-100)
printf("What is the first student's grade? ");
scanf("%d", &iScore1);

} while ((iScore1 < 0) || (iScore1 > 100));

// Ask user for second student name and score
printf("What is the second student's name? ");
scanf("%s", arrcName2);

// Check range (0-100)
printf("What is the second student's grade? ");
scanf("%d", &iScore2);

} while ((iScore2 < 0) || (iScore2 > 100));

// Ask user for third student name and score
printf("What is the third student's name? ");
scanf("%s", arrcName3);

// Check range (0-100)
printf("What is the third student's grade? ");
scanf("%d", &iScore3);

} while ((iScore3 < 0) || (iScore3 > 100));

// Ask user for fourth student name and score
printf("What is the fourth student's name? ");
scanf("%s", arrcName4);

// Check range (0-100)
printf("What is the fourth student's grade? ");
scanf("%d", &iScore4);

} while ((iScore4 < 0) || (iScore4 > 100));

// Print student name's and grades to file
fprintf(Fpointer, "%s %d\n", arrcName1, iScore1);
fprintf(Fpointer, "%s %d\n", arrcName2, iScore2);
fprintf(Fpointer, "%s %d\n", arrcName3, iScore3);
fprintf(Fpointer, "%s %d\n", arrcName4, iScore4);

// Close file

// Open file for reading
Fpointer = fopen(FILENAME, "r");

// If file is there and working properly, scan it
if (Fpointer != NULL)
// Scan file for data
fscanf(Fpointer, "%s %d", arrcName1, &iScore1);
fscanf(Fpointer, "%s %d", arrcName2, &iScore2);
fscanf(Fpointer, "%s %d", arrcName3, &iScore3);
fscanf(Fpointer, "%s %d", arrcName4, &iScore4);


// Otherwise, ERROR
printf("ERROR: File not found!");


// Display it all, just for the visual
printf("\nStudent one, %s, scored a %d.\n", arrcName1, iScore1);
printf("Student two, %s, scored a %d.\n", arrcName2, iScore2);
printf("Student three, %s, scored a %d.\n", arrcName3, iScore3);
printf("Student four, %s, scored a %d.\n\n", arrcName4, iScore4);

// Assume the first is the highest
iHighestScore = iScore1;
strcpy(arrcHighestName, arrcName1);

// Assume the first is the lowest
iLowestScore = iScore1;
strcpy(arrcLowestName, arrcName1);

// Compare score 2 to score 1
// Highest
if (iScore2 > iScore1)
iHighestScore = iScore2;
strcpy(arrcHighestName, arrcName2);


// Lowest
if (iScore2 < iScore1)
iLowestScore = iScore2;
strcpy(arrcLowestName, arrcName2);


// Compare score 3 to score 2 and 1
// Highest
if ((iScore3 > iScore2) && (iScore3 > iScore1))
iHighestScore = iScore3;
strcpy(arrcHighestName, arrcName3);


// Lowest
if ((iScore3 < iScore2) && (iScore3 < iScore1))
iLowestScore = iScore3;
strcpy(arrcLowestName, arrcName3);


// Compare score 4 to score 3, 2 and 1
// Highest
if ((iScore4 > iScore3) && (iScore4 > iScore2) && (iScore4 > iScore1))
iHighestScore = iScore4;
strcpy(arrcHighestName, arrcName4);


// Lowest
if ((iScore4 < iScore3) && (iScore4 < iScore2) && (iScore4 < iScore1))
iLowestScore = iScore4;
strcpy(arrcLowestName, arrcName4);


// Print highest and lowest scores and their respective students
printf("\nThe highest score was a %d from %s.\n", iHighestScore,
printf("The lowest score was a %d from %s.\n", iLowestScore,

// Perform average calculation and print result
dScoreAverage = (iScore1 + iScore2 + iScore3 + iScore4) / 4.0;
printf("\n\nThe test average is %.2f\n\n", dScoreAverage);

// Close file

return 0;


Answer Source

Read input2 as a string, not an integer. You can either atoi() the string to get an integer, or just write it out as a string by changing that %d to a %s.

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