Habib.Khan Habib.Khan - 2 months ago 12
C Question

How to find the position of maximum in an array in C

I have an array of 16 integer values where each value is 32 bits each as shown. I can find the maximum of the array as follows.

#include <stdio.h>
#include <conio.h>
// main program
int main(void){
int i, max;
int array[16];
array[0]=0x1;
array[1]=0x6;
array[2]=0x8;
array[3]=0xC;
array[4]=0x7;
array[5]=0x9;
array[6]=0xB;
array[7]=0x0;
array[8]=0x3;
array[9]=0x6;
array[10]=0x7;
array[11]=0x6;
array[12]=0x15;
array[13]=0x1;
array[14]=0x9;
array[15]=0x3;

// calculate max
max=array[0];

for(int i=1;i<16;i++)
{
if(max<array[i])
{
max=array[i];
}

}
printf("The max is %lx ",max);

getch();
return 0;


I want to find the position of the maximum value in the array and the position of the most significant binary 1 in the maximum value. As can be seen, the maximum value is 0x15 at position 13 in the array and the position of most significant binary 1 in the entry is 5th . How can this be accomplished in C?

Answer

put this after the printf statement. and define j at the top.

for (j=0; j<16; j++) {
    if ((max=max>>1) == 0)  break;
}

printf("the max bit is %lx ", j);

this shows the bit position in conventional notation where the 5th bit is bit 4. add a '+1' to display as bit 5.

to display the position where the max occurs:

below the 'max=array[i]' line, add the following line (after defining maxpos with the other variables)

maxpos = i;  

and change the printf to

printf("The max is 0x%02x at position 0x%02x ", max, maxpos);