Explain for loop plse i don't understand that*str

Question

https://code.sololearn.com/ci6wl04V0LgZ/?ref=app

Answer 1

I code in JavaScript. But it is the same principal: for(i = 0; i < 10; i++) at first with 'i = 0' you create a variable 'i' . Then with 'i < 10' you are setting the test condition. Basically saying the loop is true as long as i is less than 10. Then in the third part 'i++' you are saying keep increasing i by 1 until it is no longer less than 10. Or else the condition is false and the loop must stop.

Answer 2

Boopathi

Don't afraid of the unusual form of the for loop here. It doesn't bite!
All three expressions inside a for loop are optional* which in this case we've just used the loop step expression to move through each element of the array. Suppose the array s' internal representation makes up as

address value
280 n/a
279 n/a
... ...
201 n/a
200 n/a

The array occupies a memory block from 200 to 280 when get declared as

char s[80];

In case of *str, it's a simple integer pointer which gets initialized to the address of the first element of the array as

str = s

Now, str is equal to 200 as the address of the first element of the array. Every time that str increases as

++str

The next address of the array will be stored in str. (e.g. 201, 202, ...)
Also, *str in if (*str == 32), dereferences the current character pointed by the stored address in str and then compare it against the space character.

Answer 3

Corrected version of the code

#include <stdio.h>

int main() {
char s[80],*str;
int space = 0;
printf("enter the string");
gets(s);
str=s;

for( ; ; str++) {
if(*str == 32)
break ;
++space;
}
printf("%d",space);
}

The for loop traverses through the array using str pointer. Using pointer in this context makes it possible to increment the pointer with ++ operator. Then, the loop continues to cycle before the first space is encountered in the inputted character sequence. Finally, it counts the number of characters before exiting the loop and prints it out on the console screen.

Answer 4

Boopathi
Which part do you want to know more about?

Answer 5

Cont.

____
* for ( loop counter initializer ; loop condition ; loop step )
without them you've got an infinite loop as

for ( ; ; )

Which is equivalent to

while (true)

Answer 6

muppatti ramya sri

Sure. Try to experiment with it if you are willing to get the whole idea of what happens.

Answer 7

understand .but cam you explain briefly plse

Answer 8

for loop *str??????

Answer 9

without a condition for loop works????

for( ; ; i++)