Thread: convert from upper to lower

Originally Posted by Adak

123456 - The input

My thinking goes like this:

#1.
for every digit in the set of digits, print it, then print a space

#2.
for(every digit in the set of digits)
....print the digit and a space

#3.
for(i equals first digit, i is less than or equal to 6, increment i)
....printf(the digit and 1 space)

Ready to code up the loop.

It's odd to take it through these steps, because with practice, you just say "got it", and code it. But the process REALLY comes into play with any problem where you don't have an answer.

Failing anything better, start with how YOU would do it, and take that logic step by step, to your program.

i'm going to do that practice and practice
i need more problems that let me learn

Working

Code:

#include<stdio.h>
#include<string.h>
int main()
{

    char arr[100];
    int i=0;
    fgets(arr,100,stdin);
    int x=strlen(arr);
    for(i=0;i<x;i++){

        printf(" %c",arr[i]);

    }

    return 0;

}

Working

Code:

#include<stdio.h>
#include<string.h>
int main()
{

    char arr[100];
    int i=0;
    fgets(arr,100,stdin);

    while(i<strlen(arr)){

        printf(" %c",arr[i]);
        i++;
    }

    return 0;
}

Not Working i used debugger step by step it go ahead to return 0 Why?

Code:

#include<stdio.h>
#include<string.h>
int main()
{

    char arr[100];
    int i;
    fgets(arr,100,stdin);

    for(i=0;i!='\0';i++){

        printf(" %c",arr[i]);

    }

    return 0;
}

Not Working i used debugger step by step it go ahead to return 0
Why?
loop till find the Null terminator ?

Code:

#include<stdio.h>
#include<string.h>
int main()
{

    char arr[100];
    int i=0;
    fgets(arr,100,stdin);

    while(i!='\0'){

        printf(" %c",arr[i]);
        i++;
    }

    return 0;
}

Not Working i used debugger step by step it go ahead to return 0

Code:

#include<stdio.h>
#include<string.h>
int main()
{

    char arr[100];
    int i=0;
    fgets(arr,100,stdin);

    while(arr){
        if(i!='\0'){
        printf(" %c",arr[i]);
        i++;}
        else
            return 0;
    }

    return 0;
}

in the first,second Code i used strlen() that will count the Null terminator
i mean it is the same idea with the other 3 code
so what is the problem

This:

Code:

 for(i=0;i!='\0';i++){

is incorrect. You're telling the for loop to quit if i does not equal '\0'. But i is an int, and i =0 is the equivalent of i='\0', so the test evaluates to true, causing the loop to quit , before it loops.

Add this line inside the for loop. See how many times it prints the value of i:

Code:

printf("i equals: %d\n",i);

That's one of the beauties of programming - you can test your own ideas out.