How to check if all the upper-case letters are present in the input the user gives?

user_19252103 0
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I'm trying to check if all the upper-case letters are present in the input the user entered.

I tried to make an array of 26 values, 0 will represent A and 25 is Z. At first I initialize the values to 0.

After that I asked the user for input and then I checked if it matches with the ASCII. If yes, I changed the array value to 1.

After that, I make sure all the array values are 1; if yes all the letters were in the input.

I assume that the user will end the input with 0.

The input is "THE Q$@UICK BROWN FOX JUMPS OVER tHe LAZY DOG!0".

This is the code:

#include <stdio.h>

int main()
{
int z;
int x = 1;
int arr[26] = {0};

printf("enter a sentance to check if all latter in ABC are in the sentance (in upper case):\n");

while (x!=0) {
    scanf(" %d", &x);
    z = x - 65;
    if (z>=0 && z<=25) {
       arr[z]=1;
    }
}

z=0;
while (arr[z]==1 && z<26) {
    ++z;
    if (z==26) {
        printf("all the ABC in ur sentance\n");
        break;
    }
}

 printf("all the ABC does not in ur sentance\n");

    return 0;
}

There is no output and I think it's because there is a problem with the scanf, but I don't know how to solve it.

c
2 Answers
  • %d format specifier in scanf() is for reading integers, not characters. In this case, you should use getchar() instead of scanf() to read characters one-by-one.
  • The character 0 don't have the value 0. (it is 48 in ASCII).
  • Using magic numbers like 65 is not good. Using character constants like 'A' should be good in this case to make the meaning clear.

The part

while (x!=0) {
    scanf(" %d", &x);
    z = x - 65;
    if (z>=0 && z<=25) {
       arr[z]=1;
    }
}

should be:

while ((x = getchar()) != '0' && x != EOF) {
    z = x - 'A';
    if (z>=0 && z<=25) {
       arr[z]=1;
    }
}

Also note that "all the ABC does not in ur sentance\n" will be printed even after "all the ABC in ur sentance\n" is printed. You should use return 0; instead of break; to finish the execution of the function and prevent the extra string from being outputted.

user_40623540

You need to use %c to read a character and convert it to its character code. %d reads the representation of an integer.

If the character 0 ends the input, you need to compare with '0', not 0.

You can use isupper() to test if a character is an uppercase letter, rather than testing the range yourself.

The loop to check that all the characters have been entered can be simplified as I've shown below.

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

int main()
{
    int z;
    char x;
    int arr[26] = {0};

    printf("enter a sentance to check if all latter in ABC are in the sentance (in upper case):\n");

    while (1) {
        scanf(" %c", &x);
        if (x == '0') {
            break;
        }
        if (isupper(x)) {
            z = x - 'A';
            arr[z]=1;
        }
    }

    for (z = 0; z < 26; z++) {
        if (arr[z] == 0) {
            printf("all the ABC are not in your sentance\n");
            return 0;
        }
    }
    printf("all the ABC in your sentance\n");

    return 0;
}
user_14918950
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