Thread: Undefined reference to main - collect2: ld returned 1 exit status

I'm doing an assignment at school in C, but the program won't run.

I get the error: "/tmp/ccW7r5po.o:functions3.c.text+0x1b9): undefined reference to `myLog2'collect2: error: ld returned 1 exit status"

Help anyone?

Code:

#include <stdio.h>

void myTriangles (int numlines);
int myPrimeFactor (int number, int primeFactor);
void myNumbers (int startnum, int endnum);
int myLog2(unsigned int n);




int main ()
{
    int numlines, number, primeFactor, startnum, endnum, result, operasjon, f;
    printf("Choose function.\n");
    printf("1. myTriangles.\n");
    printf("2. myPrimeFactor. \n");
    printf("3. myNumbers. \n");
    printf("4. myLog2. \n");
    printf("5. reverseString. \n");
    scanf ("%d",&operasjon);
    switch (operasjon)
    {
        
        case 1:
        {
        printf("Enter number of rows!\n");
        scanf("%d",&numlines);
        myTriangles(numlines);
        }
        break;
        case 2:
        {
        printf("Enter a value.    ");
        scanf("%d",&number);
        printf("Enter a prime factor. \n");
        scanf("%d",&primeFactor);
        f =    myPrimeFactor (number, primeFactor);
        printf("%d", f);
        }
        break;
        case 3:
        {
        printf("Enter a start number.\n");
        scanf("%d", &startnum);
        printf("Enter an ending number.\n");
        scanf("%d", &endnum);
        myNumbers(startnum, endnum);
        }
        break;
        case 4:
        {
        unsigned int n;
 
            printf("Pick a positive number: ");
            scanf("%d", &n);
 
            int result = myLog2(n);
            printf("The position of the most significant bit is %d\n\n", result);
        }
    }
}


// OPPGAVE 1
void myTriangles (int numlines)
{
    int i, j;
    
    for (i=1;i<=numlines;i++) 
    {
    for (j=1;j<=i;j++)
    {
        printf("*");
    }
        printf("\n");
    }
}
// OPPGAVE 2    
int myPrimeFactor (int number, int primeFactor)
{
    int result = number % primeFactor;


    if(result == 0){
    return 1;
    }
    else
    {
    return 0;
    }
}
// OPPGAVE 3
void myNumbers (int startnum, int endnum)
{
    
        while (startnum <= endnum)
    {
        int result = myPrimeFactor(startnum, 5);
        
        if (startnum % 2 == 0 && result == 1) {
            printf("%d is even and 5 is a prime factor\n",startnum);
        }
        else if (startnum % 2 == 1 && result == 1) {
            printf("%d is odd and 5 is a prime factor\n",startnum);
        }    
        else if (startnum % 2 == 1 && result == 0) {
            printf("%d is odd and 5 is not a prime factor\n",startnum);
        }
        else if (startnum % 2 == 0 && result == 0) {
            printf("%d is even and 5 is not a prime factor\n",startnum);
        }
    startnum ++;
    }
    
// OPPGAVE 4
int myLog2(unsigned int n)
{
    int result = 0;
   
    while (n > 1)
    {
        n = n >> 1;
        result++;
    }
    return result;
}

Check your spelling, remember that C is case sensitive.

Jim

Originally Posted by jimblumberg

Check your spelling, remember that C is case sensitive.

Jim

Thanks for the reply.
I have checked my spelling, but I can't seem to find any problems at all when it comes to spelling..

The problem is not with spelling.

First of all, turn on and turn up your warning level to the highest level.

Code:

mylog.c:126:1: error: expected declaration or statement at end of input
 }
 ^

One of the other problems that could have occurred is mismatched curly braces, square brackets, and parentheses. Start on the line in the error message I have shown you, and check each function, counting delimiters to see if this might be your problem. HINT! HINT!

Use a programmers editor or IDE that will highlight matching braces, etc..., or look in the documentation how to turn it on. This will save you a lot of time and frustration.