Converting lowercase to uppercase using 2D arrays in C

Question

Here I want to convert some student names into uppercase using a 2D array. This compiles without an error, but at the execution it gives an error called 'segmentation fault'. I tried this using a 1D array but it only prints the last name which I've entered. At the end I want to calculate total integer value for the entered names separately. I'm fairly new to C language, so there may be so many errors. Any ideas to fix my code?

#include<stdio.h>

#define SIZE 6

void input(char arr[][10], int size);
void upper(char arr[][10], int size);
void findIntValue(char arr[][10], int size);

int main(void)
{
  char arr[SIZE][10] = {0.0};

  input(arr, SIZE);

  upper(arr, SIZE);

  findIntValue(arr, SIZE);

  return 0;
}

 void input(char arr[][10], int size)
{
  int i, j;

  for(i = 0 ; i < size ; i++)
 {
    printf("\nEnter the name: ");
    scanf(" %s", arr[i]);
 }
}

void upper(char arr[][10], int size)
{
  int i, j;

  for(i = 0 ; i < size && arr[i] != '\0' ; i++)
 {
    for(j = 0 ; j < 10 && arr[i][j] != '\0' ; j++)
    {
        if(arr[i][j] >= 97 && arr[i][j] <= 122)
        {
            arr[i][j] -= 32;
        }
    }
 }

 for(i = 0; i < size && arr[i] != '\0' ; i++)
 {
    for(j = 0 ; j < 10 && arr[i][j] != '\0' ; j++)
    {
        printf("\n%s\n", arr);
    }
 }
}

void findIntValue(char arr[][10], int size)
{
  int i, j;
  int total = 0;

  for(i = 0 ; i < size && arr[i] != '\0' ; i++)
 {
    for(j = 0 ; j < 10 && arr[i][j] != '\0' ; j++)
    {
        total += arr[i][j];

        printf("\n%s\t%d\n", arr, total);

        total = 0;
    }
  }
}

enter image description here

Answer 1

There are many problems in your code.

Problem-1: In the function input, you need to pass arr[i] as input to scanf

Problem-2:In the upper function, in the first loop, you are trying to read an uninitialized value of j which could lead to undefined behavior.

Problem-3:In the upper function, in the second loop, in the printf you are again using arr, whereas you should be using arr[i] and also, you don't need two loops for printing. One loop is enough.

Problem-4:The loop and print logic of findIntValue is wrong. You need to print the total and arr after the inner loop is completed. Also, printed value should be arr[i] and not arr.

Please find the corrected program below:

#include<stdio.h>

#define SIZE 6

void input(char arr[][10], int size);
void upper(char arr[][10], int size);
void findIntValue(char arr[][10], int size);

int main(void)
{
  char arr[SIZE][10] = {0.0};

  input(arr, SIZE);

  upper(arr, SIZE);

  findIntValue(arr, SIZE);

  return 0;
}

 void input(char arr[][10], int size)
{
  int i, j;

  for(i = 0 ; i < size ; i++)
 {
    printf("\nEnter the name: ");
    scanf(" %s", arr[i]);
 }
}

void upper(char arr[][10], int size)
{
  int i, j;

  for(i = 0 ; i < size && arr[i][0] != '\0' ; i++)
 {
    for(j = 0 ; j < 10 && arr[i][j] != '\0' ; j++)
    {
        if(arr[i][j] >= 97 && arr[i][j] <= 122)
        {
            arr[i][j] -= 32;
        }
    }
 }

 for(i = 0; i < size && arr[i][0] != '\0' ; i++)
 {
        printf("\n%s\n", arr[i]);
 }
}

void findIntValue(char arr[][10], int size)
{
  int i, j;
  int total = 0;

  for(i = 0 ; i < size && arr[i][0] != '\0' ; i++)
 {
    for(j = 0 ; j < 10 && arr[i][j] != '\0' ; j++)
    {
        total += arr[i][j];
    }
        printf("\n%s\t%d\n", arr[i], total);
        total = 0;
  }
}