#include<stdio.h>
#include<conio.h>
#include<math.h>

void main()
{
    double n,e;
    clrscr();
    printf("Enter any number = ");
    scanf("%lf",&n);
   
    e=log10(n);
    printf("\nlog10(%.2f) = %.2f",n,e);

    getch();
}

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Copy & paste this code in your TC & run, then you will get output.......
If you have any problem please comment below.........