Octal to Decimal Conversion in C

 

// OCTAL to DECIMAL

#include <stdio.h>

#include <math.h> 

#include <string.h> 

int main()

{

int n=0,POWER=0,i,j;

char ar1[20];

char ar2[8] = {'0','1','2','3','4','5','6','7'}; 

/*

ar2[0]=0,ar2[1]=1,ar2[2]=2,ar2[3]=3,

ar2[4]=4,ar2[5]=5,ar2[6]=6,ar2[7]=7

*/

printf("Enter any Octal Number : ");

scanf("%s",&ar1);

//let ar1 = 372

for(i=strlen(ar1)-1;i>=0;i--)

//i=2,1,0

{

for(j=0;j<8;j++)

{

if(ar1[i]==ar2[j])

{

n=n+j*pow(8,POWER);

}

}

POWER++;

/*

step 1:

ar1[2]=2=ar2[2],it means j=2

n = 0+2*pow(8,0) = 0+2 = 2

POWER=1

step 2:

ar1[1]=7=ar2[7],it means j=7

n = 2+7*pow(8,1) = 2+56 = 58

POWER=2

step 2:

ar1[2]=3=ar2[3],it means j=3

n = 58+3*pow(8,2) = 58+192 = 250

POWER=3

n = 250

*/

}

printf("\nDecimal Number = %d",n);

}

**Author**

Sukhvir Singh

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