Thread: Ashamed to ask

in C you can do this

scanf("%fx + %fy", &x, &y);
and on the input you type
2x + 3y and x and y become 2,3 respectively.

I tried this in C++

cin >> x >> "x + " >> y >>"y";

why won't it work the same?

kwigibo

Point taken, it is worded badly.

In C I can use scanf to skip over "expected input" such as the x+..y part. I tried a similar method in C++, which I thought would have the same effect. But it didn't how do I do it.

run the code below, and it'll show what I mean. use input such as

2x + 3y
76x + 9y
1x + 1y
etc

respectively you should get the outputs
2,3
76,9
1,1

Code:

#include <stdio.h>

int main() {
    int x,y;
    scanf("%dx + %dy", &x,&y);
    printf("\n\n%d\n%d\n",x,y);
    return 0;
}

just use scanf. or if mixing input streams bothers you, read in a string and use a flavor of scanf to parse it.

Any suggestions on "a flavor of scanf"? and perhaps a small/simple example of its use which I could plugin to a file and run

Here's a flavor.

Code:

#include <stdio.h>
#include <iostream>

using namespace std;

int main() {
    char line[80];
    int x,y;
    cin.getline(line,80);
    sscanf(line,"%dx + %dy", &x,&y);
    printf("\n\n%d\n%d\n",x,y);
    return 0;
}

There's probably a way to do this using the strstream class from the Standard C++ Library. However I don't use strstream enough to know how.