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Here's my code. Please help.
Thanks in advance.
Code:#include<stdio.h>
int main(void)
{
char abc[] = {"MmyNnameIisMmonk"};
char *ptr = abc;
int i = 0;
for(i = 0; i < (sizeof(abc) / sizeof(char)); i++) {
if(abc >= 'A' || abc <= 'Z') {
ptr++;
printf("%c ", ptr[i]);
}
}
}
First of allLook at that code and tell me what you think it does. What is abc pointing to each time through the loop? When is it being changed?Code:if(abc >= 'A' || abc <= 'Z')
Aside from that you should rearrange the A and the Z, and use strlen function in the string.h library. It returns the string length back to you, this will work well with your for loop.
ex.)
Don't forget to include the string.h library at the top :)Code:for(i = 0; i <strlen(abc); i++)
isn't the 'A' and 'B' used to pass throught the ASCII table values? Hence avoiding all the Uppercase letters? :confused: Thank You for your reply
Think about this carefully. Draw it out on a "number line" (letter line?):Code:if(abc >= 'A' || abc <= 'Z')
"OR" (||) means all the characters covered by either of the two conditions. That means every possible character.Code:. . . A B C D E F G H I J K L M N O P Q R S T U V W X Y Z . . .
+------------------------------------------------------> abc >= 'A'
<-------------------------------------------------------+ abc <= 'Z'
"AND" (&&) on the other hand, means only letters covered by both of the conditions. In this case, it would be only the uppercase letters.
You really want the reverse of that, so think about what you should change ">=" and "<=" to. Hint, "<=" is not the opposite of ">=".
But, you could just #include <ctype.h>, and use the isupper() function instead. Easier and more portable.
You need to refer to abc as, abc[i] instead of just abc in your for loop.
The exercise demands to achieve it using math. I want to skip all the uppercase case letters.
That means all characters between and including A and Z :confused: is it
Please Help.Code:(abc[i] >= 'A' || abc[i] <= 'Z')
Warning: a.c: In function ‘main’:a.c:40:17: warning: initialization makes pointer from integer without a cast [enabled by default]
a.c:45:16: warning: comparison between pointer and integer [enabled by default]
a.c:45:30: warning: comparison between pointer and integer [enabled by default]
O/P : Segmentation fault(core dumped)
You should use strlen to calculate how many times your for loop should run. As well as refer to abc as abc[i] that way it will not always point to the beginning of the string.
It's not good practice to use strlen in a for loop as you posted because strlen will be called every time through the loop. This gives the loop O(n*n) time complexity. A better method is to save the return value of strlen and compare against that. Another good method is to check for end of string manually (check for null terminator). This last method avoids iterating through the string twice (once in strlen and once in the for loop).Quote:
Originally Posted by camel-man
Ahh yes, that would be better. I am so rusty with strings, always forgetting about that null terminator :D
One way:
Code:#include <stdio.h>
#include <string.h>
int main(void) {
char abc[] = {"MmyNnameIisMmonk"};
int i = 0, len;
len = strlen(abc);
for(i = 0; i<len; i++) {
if(abc[i] >= 'a' && abc[i] <= 'z') {
printf("%c", abc[i]);
}
else {
if(i)
printf(" ");
}
}
printf("\n");
return 0;
}
This is bad since strlen will be called for every character in abc.Quote:
Originally Posted by camel-man
if abc is 1000 chars long, each of the chars in abc will be looked at 1000 times. thats 1000 * 1001 , 1 Million+ checks for the string terminator ('\0').
sizeof(abc)/sizeof(char) is a const that will be evaluated once by most compilers , it's one char too long though.
Thanks for all the help guys. I've come up with this:
Thought I'd learn some subnetting today and then go to college. But ended up doing this program :tongue:Code:#include<stdio.h>
int main(void)
{
char abc[] = {"Mmy Nname Iis Mmonk"};
int i = 0;
for(i = 0; abc[i] != '\0'; i++) {
if(abc[i] >= 'a' && abc[i] <= 'z') {
printf("%c: %d ", abc[i], abc[i]);
}
else if(abc[i] == ' ') {
printf("\n");
}
}
printf("\n");
return 0;
}
O/P:
m: 109 y: 121
n: 110 a: 97 m: 109 e: 101
i: 105 s: 115
m: 109 o: 111 n: 110 k: 107
You should be aware that the method that you use requires the letters of the alphabet to contiguous in value in the character set. This is very likely to be true these days since you will almost certainly be using ASCII or something incorporating ASCII, but in theory it is not guaranteed, hence isupper is a better option.Quote:
Originally Posted by Sid_TheBeginner
Instead of excluding uppercase letters, your program now includes only lowercase letters and spaces. If you're okay with this, well and good, but note the difference ;)Quote:
Originally Posted by Sid_TheBeginner