Crazy stuff can happen :S

**stam** · 12-23-2010

Ok the program is done but when it runs and u start give what it asks
Example:

How many athletes; 2 (we give 2)
***Give Athletes Data:
Lastname: Messi
First Jump: 5.6
etc....

Instead of the above it asks for:

How many athletes; 2 (we give 2)
***Give Athletes Data:
Lastname: First Jump: 5.6
etc....
IT SKIPS the first lastname but it asks u for the second properly
What the heck is that ^^

Code:

#include <cstdlib> 
#include <iostream> 

using namespace std; 
struct athlete 
{ 
    char lastname[40]; 
    float p1,p2,p3,p4; 
}; 


void show_athletes(athlete A[], int MAX_ATHLETES); 
int main(int argc, char *argv[]){ 
    int MAX_ATHLETES;
    cout << "How many Athletes; ";
    cin >> MAX_ATHLETES;
    athlete* A = new athlete[MAX_ATHLETES];
    int i;
    for(i=0;i<MAX_ATHLETES;i++){ 
       printf("\n*** Give Athletes Data: \n"); 
       printf("Lastname: "); 
       gets(A[i].lastname); 
       do{ 
            printf("First Jump: "); 
            scanf("%f",&A[i].p1);getchar(); 
       }while(A[i].p1<0); 
       do{ 
            printf("Second Jump: "); 
            scanf("%f",&A[i].p2);getchar(); 
       }while(A[i].p2<0); 
       do{ 
            printf("Third Jump: "); 
            scanf("%f",&A[i].p3);getchar(); 
       }while(A[i].p3<0); 
       do{ 
            printf("Fourth Jump: "); 
            scanf("%f",&A[i].p4);getchar(); 
       }while(A[i].p4<0); 
    } 
     printf("Press Enter to Show Athletes with Jumps longer than 7.50"); 
     getchar(); 
     show_athletes(A,MAX_ATHLETES); 
     system("PAUSE"); 
    return EXIT_SUCCESS; 
} 
void show_athletes(athlete A[],int MAX_ATHLETES){  
    int i; 
    for(i=0;i<MAX_ATHLETES; i++){ 
       if (A[i].p1>7.5 || A[i].p2>7.5 || A[i].p3>7.5 || A[i].p4>7.5) {
          printf("The Athlete:%40s Jumped Longer than 7.50\n",A[i].lastname);
          printf("Ta almata tou einai:\n%f\n%f\n%f\n%f\n",A[i].p1,A[i].p2,A[i].p3,A[i].p4); }
    } 
}

**tabstop** · 12-23-2010

If you're including iostream, then you don't have scanf and printf and gets, you have >> and << and getline, so this shouldn't (strictly) be compiling at all. Use << and >> and getline.

**stam** · 12-23-2010

i just changed the

Code:

gets(A[i].lastname)

with

Code:

cin >> A[i].lastname

and worked perfectly
Thnx for help

**hk_mp5kpdw** · 12-23-2010

Code:

int main(int argc, char *argv[]){ 
    int MAX_ATHLETES;
    cout << "How many Athletes; ";
    cin >> MAX_ATHLETES;
    athlete* A = new athlete[MAX_ATHLETES];
    int i;
    for(i=0;i<MAX_ATHLETES;i++){ 
       printf("\n*** Give Athletes Data: \n"); 
       printf("Lastname: "); 
       gets(A[i].lastname); 
       do{ 
            printf("First Jump: "); 
            scanf("%f",&A[i].p1);getchar(); 
       }while(A[i].p1<0);

What is happening is the cin >>MAX_ATHLETES call reads the number and stores it but leaves the newline character in the input stream. When you reach the gets call, it sees the remaining newline and interprets this as the user (you) pressing the enter key to terminate input. The newline char is consumed by the gets call leaving the input stream now empty and storing nothing in the lastname field and the program proceeds past this point which you instead expected it to stop at. The subsequent scanf call blocks (waits for input) until a value is entered and the newline is once again pressed.

**Eman** · 12-23-2010

Excellent explanation.

i have had this annoying problem before when doing C last year

.

you have to use getchar() or getch() to remove the newline left in the input stream

Code:

       while(getchar()!='\n') ; // will flush the buffer as opposed to fflush(stdin)(wrong!)

works as well.

**Xupicor** · 12-23-2010

@up - if you're talking about the "getch()" from conio.h (old Borland header), then it will not read the character from the standard input stream. It will wait for the "real" keystroke using system dependent features.

**Eman** · 12-27-2010

oh right! Thanks for letting me know! :P

**Elysia** · 12-30-2010

gets should be std::getline, printf should be std::cout, scanf should be std::cin.
You should stick to either C or C++, not a mix of both.

**iMalc** · 12-30-2010

And of course...
Never use gets under any circumstances. Use fgets instead.

(which Elysia would normally tell you about, but forgot today)

**User-_-Name** · 12-30-2010

Originally Posted by Elysia

gets should be std::getline, printf should be std::cout, scanf should be std::cin.
You should stick to either C or C++, not a mix of both.

Amen... I don't understand why everyone insists on using these complex, time-consuming processes when you can simply use

Code:

cout << "Last name: ";
cin >> lastname;
cout << "First Jump: ";
cin >> firstjump;

and etc

**rogster001** · 12-30-2010

amen nada, its called backward compatability mate, and though i cant neccesarialy include myself, knowledge of the rawer roots of the language lend insight and understanding- walking before running, if you know latin you can get a handle on many modern languages- backward compatability.

**Eman** · 12-30-2010

i learnt C first, and sometimes you can't automatically help but type a printf statement..
I don't know whether it is my lack of experience with C++ but there are times where I have no choice but to use C code.

**rogster001** · 12-30-2010

slainte eman, all the best. my point is though elysia speaks with authority, and champions c++ due to that depth of knowledge and familiarity with the idiom-so amen wot?

**Eman** · 12-30-2010

haha, Slainte?
well done on your research, lol!
Hopefully I gain that same amount of depth..which seems rather bleak at this stage

**Elysia** · 12-31-2010

Originally Posted by Eman

i learnt C first, and sometimes you can't automatically help but type a printf statement..
I don't know whether it is my lack of experience with C++ but there are times where I have no choice but to use C code.

This is understandable. But as you continue learning a new language, it will grow on you and you will be able to forget those old C horrible, unsecure functions. Just keep practicing!

Originally Posted by iMalc

(which Elysia would normally tell you about, but forgot today)

Actually, I would had this been C, but it isn't. There is no reason to use gets/fgets in C++ (unless you have a very particular requirement, but I assume this isn't the case here).

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