Randomizing numbers and words

[Lachrymose]

Hey guys, I need some help with random numbers and words.

I am trying to make a random motion formula problem for physics class.

[highlight=cpp] double gravity = 9.81;
double mass = rand() % 100;
double acc = rand() % 100;
double fg = gravity * mass;
double fnet = mass * acc;
srand(time(0));


cout << "A car accelerates at " << acc << "mps and has mass is " <<mass<< "kg. Find fnet and fg" <<endl;[/highlight]

I have no idea where to start for the random words. But I want it to be like "car, bike, train, etc". And for the numbers, I can't get them to go random. They turn out to be 67 and 41. I can use the rand() function alone but then the numbers are too high. Thanks in advance.

 

[slicer4ever]

for using the random words, i'd personally save all the string's i'd use into an array:

[highlight=cpp]
#include <stdio.h>
#include <time.h>
int main(int argc, char **argv){
//place srand here
srand(time(NULL));
char **Words = new char*[3];
Words[0] = new char[50];
sprintf(Words[0],"A Car sentence");
Words[1] = new char[50];
sprintf(Words[1],"A Bike sentence");
Words[2] = new char[50];
sprintf(Words[2],"A Train sentence");
float gravity = 9.81;
float mass = rand() % 100;
float acc = rand() % 100;
float fg = gravity * mass;
float fnet = mass * acc;
int Sentence = rand() % (3);
printf("%s is moving at: %f, with a mass of: %f",Words[Sentence], acc, mass);
for(int i=0;i<3;i++) delete[] Words;
delete[] Words;
}
[/highlight]
and it's that simple
just make sure you call srand(time(NULL)); at the top of your main function, also please use floats from now on, thirdly their's not much sense to use floats with your random numbers since it'll only return int's=-)

 

[Lachrymose]

Thanks for the reply man!

Lots of help.

 

[slicer4ever]

not a prob=-)

 

[Thulium]

[highlight=cpp] char **Words = new char*[3];
Words[0] = new char[50];
sprintf(Words[0],"A Car sentence");
Words[1] = new char[50];
sprintf(Words[1],"A Bike sentence");
Words[2] = new char[50];
sprintf(Words[2],"A Train sentence");[/highlight]
That's a really ineffective method to go about this, seeing the strings are stored and pointed to anyways. A much better approach would be:

[highlight=cpp]#include <stdio.h>
#include <time.h>

char *Words[] = {
"A Car sentence",
"A Bike sentence",
"A Train sentence",
};

int main(int argc, char **argv) {
float gravity = 9.81;
float mass = rand() % 100;
float acc = rand() % 100;
float fg = gravity * mass;
float fnet = mass * acc;
int sentence = rand() % 3;
printf("%s is moving at: %f, with a mass of: %f", Words[sentence], acc, mass);
}[/highlight]

 

[Lachrymose]

Thanks for the tips.

 

[slicer4ever]

[highlight=cpp] char **Words = new char*[3];
Words[0] = new char[50];
sprintf(Words[0],"A Car sentence");
Words[1] = new char[50];
sprintf(Words[1],"A Bike sentence");
Words[2] = new char[50];
sprintf(Words[2],"A Train sentence");[/highlight]
That's a really ineffective method to go about this, seeing the strings are stored and pointed to anyways. A much better approach would be:

[highlight=cpp]#include <stdio.h>
#include <time.h>

char *Words[] = {
"A Car sentence",
"A Bike sentence",
"A Train sentence",
};

int main(int argc, char **argv) {
float gravity = 9.81;
float mass = rand() % 100;
float acc = rand() % 100;
float fg = gravity * mass;
float fnet = mass * acc;
int sentence = rand() % 3;
printf("%s is moving at: %f, with a mass of: %f", Words[sentence], acc, mass);
}[/highlight]

indeed that method is a far better method