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cprintfaddition
Vaibhav Agarwal
Vaibhav Agarwal

Reputation: 1142

add two numbers without using operators

I was searching for how to add two numbers without using ('+'/'++') and went through link. But, I also found this solution:

#include<stdio.h>
int add(int x, int y);

int add(int x, int y)
{
    return printf("%*c%*c",  x, ' ',  y, ' ');
}

int main()
{
    printf("Sum = %d", add(3, 4));
    return 0;
}

Can somebody explain what's happening in add function?

Upvotes: 1

Views: 905

Answers (2)

Tudor
Tudor

Reputation: 62469

Well what happens is this: the * before c tells printf that:

The width is not specified in the format string, but as an additional integer value argument preceding the argument that has to be formatted.

Hence this means that the first space character will be printed with a width of a and the second one with a width of b. At the same time printf returns the number of characters printed, which is actually a + b characters.

Upvotes: 1

Daniel Fischer
Daniel Fischer

Reputation: 183978

return printf("%*c%*c",  x, ' ',  y, ' ');

The * in the printf format means that the field width used to print the character is taken from an argument of printf, in this case, x and y. The return value of printf is the number of characters printed. So it's printing one ' ' with a field-width of x, and one with a field-width of y, makes x + y characters in total.

Upvotes: 2

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