CODEWITHSUNDEEP
c
Prophenius
Prophenius

Reputation: 23

The output of a certain part of my for loop

#include <stdio.h>
int num, i, k, a[5];
int main() {
    a[0]=2;
    a[1]=11;
    a[2]=12;
    a[3]=16;
    a[4]=28;
    num=a[1+3]
    i=4;
    while(num>0){
        a[i]=num%4;
        num=num/3;
        printf("%d ",num);
        i--;
    }
    printf("8\n");
    for(k=0;k<5;k++){
        printf("%c ",65+a[k]);
    }
    printf("\n);
}

The output of this program is:

9 3 1 0 8

C B D B A

I understand completely how the output for the first line is but am rather confused about the 2nd part.

for(k=0;k<5;k++){
    printf("%c ",65+a[k]);

This bit here confused me as the loop the first time from my understanding should go k=0 then print %c which comes from 65+a[k] which k is currently 0 so 65+a[0]. From the earlier part of the where its setting we see a[0]=2 and 65+2 is 67 which is the character "C". which is correct on the output but if I follow this same logic for the 2nd loop 65+a[k] where k=1 so 65+a[1] and a[1] is 11 and 65+11 is 76 that would equal the character "K" but that's wrong as it should be the character "B".

I feel that this line of code is where im missing something:

a[i]=num%4

but it doesn't actually set a number so still confused.

Any help is appreciated

Upvotes: 2

Views: 62

Answers (1)

Ayushi Jha
Ayushi Jha

Reputation: 4023

a[i]=num%4 does set the number. This is how:

In your loop:

 while(num>0){
    a[i]=num%4;
    num=num/3;
    printf("%d ",num);
    i--;
}

num varies as in the first line of output. 

a[i]=num%4;

actually sets the values in the array as follows:

Initially, i=4 and num=28. Therefore,

a[i]=num%4; sets a[4] as 28%4=0. Therefore, your last character is A+0=A.

Then i=3, and num=9. Therefore,

a[i]=num%4; sets a[3] as 9%4=1. Therefore, your second last character is A+1=B.

Then i=2, and num=3. Therefore,

a[i]=num%4; sets a[2] as 3%4=3. Therefore, your third last character is A+3=D.

Then i=1, and num=1. Therefore,

a[i]=num%4; sets a[1] as 1%4=1. Therefore, your fourth last character is A+1=B.

Then i=0, and num=0. Therefore,

We do not enter the loop. a[0]=C, its initial value.

Hence we get: C B D B A

Upvotes: 2

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